1. Introduction

Conventional displays are engineered toward transparency: higher resolution, sharper edges, and more accurate colour reproduction. This trajectory assumes that clarity equals value. Yet media and art traditions—from analogue film grain to impressionist blur—show that ambiguity can also communicate. This work asks whether a low-fidelity, materially grounded display can offer experiential qualities that precision-engineered screens cannot.

The object of investigation is a simple configuration: acrylic sheets arranged to expose their cross-sections in a slit-like pattern. During preliminary material exploration, an unexpected perceptual phenomenon emerged (Figure 1). Objects viewed through the acrylic cross-sections appeared to “float” forward, occupying a perceived depth in front of the physical surface. This floating depth illusion was not designed—it arose serendipitously from the inherent optical properties of the material: refraction through thickness and selective occlusion by the acrylic walls. Its emergence exemplifies what this research terms Creative Unintentional Use—intentionally using a system in ways that deviate from its intended, normal use for the purpose of creative practice.

This paper presents two complementary investigations: (1) iterative design research to characterise the optical mechanisms of the floating depth illusion in a linear slit configuration, and (2) a qualitative field study with four IIT Bombay students to examine how digital natives perceive and engage with the artefact’s ambiguity in everyday settings.

Design research shows that the illusion arises when acrylic walls suppress direct light while refracted light through the material body persists, creating a motion-dependent depth cue that works with monocular vision. The qualitative study shows active physical exploration, diverse narrative projection (from “hologram” to “ghost”), and reinterpretation of the body through the material (“Cartoon-like Hand”). Rather than confirming “ambiguity equals defect,” participants often valued blur and abstraction.

The contributions of this work are: (1) optical and perceptual characterisation of the floating depth illusion in a linear acrylic slit configuration; (2) an interpretivist field study documenting how digital natives perceive and engage with acrylic cross-section displays; (3) a thematic model of user experience organised around Synced Movement, The Floating Image, Transformation of Self, and Magic & Play; and (4) a design argument for visual ambiguity and material intelligence as productive resources in HCI display design.

2. Background and Related Work

2.1 Display Technologies and Their Limitations

Conventional displays present content within fixed rectangular frames. Advanced alternatives—AR, AIRR, parallax-barrier and lenticular systems, volumetric displays, and light field displays—offer richer spatial effects, but often face crosstalk, narrow viewing zones, perceptual inconsistencies (e.g., the Pulfrich effect), and cost/complexity. More fundamentally, they share a fidelity-first philosophy. This paper explores the opposite direction: materiality, ambiguity, and unexpected phenomena as design resources.

2.2 Creative Unintentional Use as a Research Methodology

This research employs “Creative Unintentional Use,” defined as “intentionally using a system in ways that deviate from its intended, normal use for the purpose of creative practice.” It aligns with Boden’s creativity criteria—new, surprising, and valuable—and relates to Critical Making / Research through Design, but focuses specifically on discovering unintended potentials through material misapplication. Bridle’s call to rethink technological “natural order” frames this orientation.

2.3 Material-Driven Design and Material Intelligence

Material-Driven Design (MDD) positions material properties—its “materiality”—as the primary driver of design decisions rather than starting from a predetermined application. This research aligns with MDD while extending it through the concept of material intelligence: the notion that materials “know” how to behave optically in ways that exceed designer intention. The acrylic cross-section’s floating depth illusion exemplifies material intelligence—refraction and internal reflection produce perceptual effects that no engineering specification anticipated.

2.4 Distinction from Existing Acrylic and 3D Display Applications

Conventional acrylic edge applications focus on edge polishing, edge-lit lighting (using acrylic as a light guide plate), and edge banding—techniques that treat the edge as an aesthetic surface. This research differs fundamentally: it treats the edge as an optical medium through which to “look into” the material’s cross-section, leveraging thickness as a refractive medium and parallax barrier. Unlike autostereoscopic displays (parallax barriers, lenticular lenses) that rely on precision micro-structured surfaces, this work exploits the bulk optical properties of the acrylic. Unlike fibre optic faceplates that transfer images to a material surface, this work creates floating perceptions in front of the material. Unlike passive volumetric displays that place physical scatter points within a 3D volume, this work optically displaces a 2D background image to create the perception of volumetric depth.

2.5 Phenomenology and Qualitative Research in HCI

The qualitative field study component adopts an interpretivist paradigm grounded in phenomenology—the philosophical study of the structure of subjective experience and meaning-making. In this paradigm, reality is pluralistic and constructed: the “reality” of the acrylic display changes depending on the viewer, and measuring the refractive index of the material cannot explain why one participant sees a “ghost” while another sees a “hologram.” Knowledge is generated through the interaction between researcher and participants rather than through objective variable measurement. Research through Design and phenomenological approaches in HCI have established that first-person accounts and thematic analysis of lived experience can yield design knowledge that controlled experiments cannot capture.

3. Research Questions

This work is organised around two interconnected research questions:

Design Research Question: How can Creative Unintentional Use of acrylic-sheet cross-section configurations reveal emergent optical phenomena and inform materiality-based display design in HCI?

Qualitative Research Question: How do digital natives perceive and interpret the visual ambiguity of acrylic cross-section displays, and what kinds of emotional engagement and embodied interaction arise from this encounter?

Secondary questions include: What specific perceptual illusions emerge and under what material conditions? How does the “low resolution” quality of the acrylic display function experientially—as defect or as resource? What novel HCI display expressions and spatial interactions are suggested by the materially generated perceptual effects?

4. Methodology

4.1 Integrated Approach: Two Complementary Strands

This research combines design research through making with qualitative phenomenological field inquiry. The strands are complementary: design research characterises optical mechanisms, while fieldwork characterises perceptual and emotional experience. Optical analysis alone misses interpretive richness; qualitative accounts alone lack mechanistic grounding for design.

4.2 Strand 1: Design Research through Creative Unintentional Use

The design research strand uses Creative Unintentional Use as its core method. Instead of specifying target optics in advance, iterative prototyping with acrylic slits emphasised hands-on making, observation of emergent behaviour, and documentation. Unexpected outcomes were treated as data rather than noise. The primary prototype family used 1 mm slit spacing with 1 mm and 2 mm acrylic thickness. Emergent phenomena—floating depth, moiré, colour dispersion, and fisheye-like distortion—were documented through photographs and field notes. This approach aligns with Material-Driven Design while extending it through intentional misapplication. The methodology also draws on material speculation and craft-based inquiry in design research, both of which treat the making process itself as a site of knowledge generation.

4.3 Strand 2: Qualitative Field Study—Interpretivist Paradigm

The qualitative strand adopts an interpretivist paradigm characterised by:

• Relativist Ontology: Reality is pluralistic and subjective, not a single objective fact. The “reality” of the acrylic edge is dynamically constructed through the interaction between the viewer’s mental model and the material. Physically, it is a block of plastic; experientially, for some it is a “volume of light” and for others a “magic box.”
• Subjectivist Epistemology: Knowledge is generated through researcher–participant interaction, not objective measurement. “Filter” framings of distortion were co-created in dialogue (explicit in P2’s “Photoshop filter” metaphor and echoed by P4), rather than treated as pre-existing external facts.
• Value-Laden Axiology: The research is explicitly driven by aesthetic values of curiosity and playfulness rather than functional efficiency. The researcher’s shift from a “functionalist” mindset (treating ambiguity as defect) to an interpretivist one (treating ambiguity as resource) is itself part of the research narrative.

The methodology is qualitative and phenomenological, using field observation and semi-structured interviews to understand the why behind participant metaphors and physical behaviours—questions that rating scales and structured measurement instruments cannot address.

5. The Acrylic Cross-Section Display System

This section describes the optical mechanisms of the acrylic cross-section display and the prototype configurations developed through iterative making.

5.1 Linear Slit Configuration

The floating depth illusion in the linear slit configuration arises from two interacting optical mechanisms: refraction through material thickness and selective occlusion by acrylic walls. Prototypes were constructed using acrylic sheets with 1 mm slit spacing and two thickness variants: 1 mm and 2 mm (Figure 2).

5.1.1 Basic Refraction and Slit Enhancement. Acrylic (refractive index ≈1.49) bends light passing through its thickness. Objects positioned behind the acrylic appear displaced toward the viewer, creating the perception of forward depth. A solid acrylic block produces this effect alone, but the slit configuration significantly enhances it. When acrylic sheets are arranged with gaps between them, the acrylic walls act as selective occluders—analogous to a macro-scale louver structure. Unlike micro-louver technology designed primarily for occlusion and privacy, this configuration exploits refraction-induced displacement (floating) rather than mere blocking.

5.1.2 Viewing Angle Dependency and Depth Cue Generation. At normal (head-on) viewing, the visual system receives two mixed signals: (1) the floating image—light refracted through the acrylic body—and (2) the regular image—light passing directly through the gaps. The resulting double-image perception weakens the depth effect. When the viewing angle is tilted, the acrylic walls selectively occlude the regular image while allowing the floating image to persist (Figure 3). This motion-dependent separation between the two images creates a strong depth cue interpreted by the brain as evidence of genuine 3D displacement. Critically, this depth cue functions with monocular vision, requiring no specialised viewing equipment.

5.2 Comparison with Existing Display Technologies

Table 1 contrasts the acrylic cross-section display with related technologies. The key distinction is a shift from surface microstructures/treatments to edge- and thickness-based optics—a different design philosophy based on Creative Unintentional Use of bulk material properties rather than precision surface engineering.

6. Qualitative Field Study

6.1 Research Objective and Rationale

Following the design discovery of the floating depth illusion, a qualitative field study investigated how digital natives perceive and interpret the artefact’s ambiguity. The study was motivated by reflexive recognition of an initial “functionalist” bias (treating blur as defect) and therefore foregrounded participant experience over predetermined criteria.

6.2 Participants and Context

Four participants (N = 4) were recruited from IIT Bombay (Table 2). All were students in their 20s, constituting a population of digital natives—individuals who have grown up with Retina displays and 4K smartphones—making them an appropriate lens through which to study encounters with a low-resolution, analogue artefact. The deliberate contrast between the heavy, analogue materiality of the acrylic block and the sophisticated everyday digital devices of the participants was a core contextual design choice.

Sessions were conducted in informal settings: rooms, cafes, and classrooms (Figure 4). Informal settings were chosen intentionally to observe natural, uncoerced interactions rather than controlled laboratory behaviour, and to contrast the analogue materiality of the prototype against the everyday digital context of the participants.

6.3 Interview Protocol and Data Collection

Semi-structured interviews were recorded with participant consent, including permission to use photographs in documentation. The protocol addressed three thematic areas:

1. Perceived Nature of the Artifact: Exploring how participants feel the presence of the object (“What is this?”, “How would you describe what you’re experiencing?”).
2. Impact of Physical Intervention: Observing how induced physical actions (e.g., tilting the object, moving one’s head) alter sensory perception of the image (“What happens when you tilt it?”, “Does movement change what you see?”).
3. Interpretation of the Blur: Investigating how participants interpreted the visual ambiguity (“Why do you think the image looks this way?”, “Does it remind you of anything?”).

The interviewer used open-ended prompts and avoided technical vocabulary (“refraction,” “parallax,” “optical illusion”) to reduce priming. Observations captured spontaneous behaviours including tilting, squinting, placing hands behind the acrylic, and holding the block up to the face.

6.4 Data Analysis

Thematic analysis was conducted at the utterance level. Initial codes were generated inductively from participant statements and iteratively grouped into higher-order themes. Consistent with the interpretivist paradigm, categories emerged from data rather than being imposed a priori. Reflexive field notes were included in analysis.

7. Results

7.1 Optical and Perceptual Findings from Design Research

7.1.1 Floating Depth Illusion (Linear Configuration). Iterative prototyping confirmed the floating depth illusion. The effect is strongest at oblique angles and with 2 mm acrylic (vs. 1 mm), suggesting that thickness amplifies refraction-induced displacement. Motion-dependent separation between floating and regular images yields a monocular depth cue, unlike conventional autostereoscopic displays that rely on binocular disparity.

A particularly notable finding, corroborated by participant P4’s phenomenological account, concerns the role of viewing distance. At close range, the eye focusses on the acrylic surface itself, treating the slit gaps as textural elements; at a greater viewing distance, the eye “fills in” the slit pattern—consistent with Gestalt completion—and the content behind the slits is perceived as a unified, screen-like image. Furthermore, at sufficiently oblique angles, the source material behind the slit array becomes entirely occluded and the refracted image fills the entire viewing aperture, producing what might be termed a “complete screen” percept. This viewing-angle and distance dependency implies that the artefact is not a single display but a family of perceptual states that the viewer navigates through deliberate positional change.

7.1.2 Emergent Secondary Phenomena. Beyond the primary floating depth illusion, prototyping revealed additional emergent optical phenomena: moiré patterns from the regular slit geometry, colour dispersion effects through the refractive medium, and viewpoint-dependent texture variations. These secondary phenomena were not anticipated and represent additional design resources within the same material configuration.

7.2 Qualitative Field Study Themes

Thematic analysis of field observations and interview transcripts yielded four interconnected themes organised around a central experiential arc (Figure 5).

7.2.1 Theme 1: Synced Movement. Participants did not passively observe the acrylic display; they actively engaged in physical exploration. The experience required physical synchronisation—tilting the object or moving one’s head—to reveal the floating image. P2 noted: “Its depth is still there, but the depth increases when I turn it like this.” P3 described: “Depending on me, how I am seeing… Continuous movement.” P3 also emphasised the interactive quality: the experience is not fixed but responsive to the viewer’s own body position.

This physical engagement represents a fundamental departure from conventional screen interaction, where the viewer is a stationary consumer. With the acrylic display, value is not inherent in the static object but emerges at the moment of physical engagement. Two sub-themes describe the quality of this engagement: Object Tilt (physically rotating the artefact in one’s hands) and Interactive (the continuous, responsive relationship between viewer movement and visual change).

7.2.2 Theme 2: The Floating Image. All four participants reported perceiving depth distinct from a flat screen. P1: “It is giving me a similar feeling without the 3D glass.” P1 also stated: “It appears to be more deep.” P4 described: “Text seems to be floating.” The content optically detached from the surface, creating the perception of a layered, three-dimensional presence.

P4 offered the richest phenomenological account of this depth quality, drawing on his physics background to describe a viewing-distance dependency: at close range the slits are individually visible, whereas standing further back the slit pattern “fills in” and a unified floating image appears. He also noted that at a strongly oblique angle the underlying source material disappears entirely and the refracted image fills the whole viewing aperture—“like watching a screen.” This physics-informed participant account independently corroborates the design research finding of the “complete screen” percept at oblique angles.

Four interpretations of this floating quality emerged: Mirage Effect (P1: “I feel it is more like a mirage”), Hologram-like (P4: “Like a hologram”), Magic & Play (supernatural and performative metaphors), and Transformation of Self (the viewer’s own body seen through the material). The diversity of these interpretations is theoretically significant: the same physical phenomenon—refraction-induced displacement—generated radically different phenomenological accounts depending on the participant’s conceptual framework.

7.2.3 Theme 3: Transformation of Self. A particularly unexpected finding was reinterpretation of participants’ own bodies through the acrylic display. P2 described her hand as “Cartoon hand… not realistic.” P4 observed: “Doesn’t look like human fingers.” P4 also held the acrylic block to his face and reflected: “I’m looking like a ghost here. People will scare and move. Ah, it’s interesting, no?” P1 similarly noted: “I mean it creates a perception that there is multiple glass attached but it is not broken.”

This Transformation of Self theme suggests that the visual abstraction introduced by the acrylic extends not merely to external objects but to the viewer’s own body—functioning as an aesthetics of abstraction that distances body image from its everyday realistic rendering. P2’s “Cartoon-like Hand” description suggests that this distancing was experienced as playful rather than disturbing, potentially because the level of abstraction keeps the image well short of the “uncanny valley.”

7.2.4 Theme 4: Magic & Play. P3 and P2 interpreted the artefact through registers of magic and the supernatural. P3: “I remember of the magic shows…” P2: “Looking like a ghost.” These metaphors cluster around Magic & Play, suggesting that the acrylic display functions as an open canvas onto which participants project personal narratives drawn from science fiction, fantasy, and performance. The blur and distortion, rather than blocking communication, invite interpretation.

7.2.5 Cross-Cutting Finding: Multiplicity of Interpretations. Despite observing the same optical phenomenon, participants’ metaphors diverged markedly: P4 (with a physics background) described a “hologram,” while P3 and P2 (more emotionally expressive) invoked “magic show” and “ghost.” P2 explicitly framed the effect as analogous to a “Photoshop filter,” while P4 offered a compatible framing of perceptual mediation. This divergence is not noise to be eliminated but a structurally significant finding: the acrylic display does not impose a single reading but affords multiple interpretive projections. Ambiguity is the mechanism of this openness.

Notably, P3—a design student who habitually evaluates objects in terms of user intent—spontaneously refused the “screen” categorisation: “I see it as a material, not as a screen.” This is a significant finding for the research programme. P3’s designation of the artefact as material rather than medium aligns directly with the Material-Driven Design framework and with the concept of material intelligence developed in this paper. The artefact’s resistance to screen-classification is not a failure of design communication but an expression of its ontological character: it is a material configuration that generates perceptual effects as a side-product of its optical properties, not a display device that delivers content through an interface. P3’s spontaneous categorisation, made without theoretical prompting, validates this distinction from the user side.

7.2.6 Negative Case and Design Boundary. The field data also contained a clear negative case that sets practical design boundaries. P2 repeatedly reported that, while the optical effect was “interesting,” the artefact did not by itself evoke strong emotion, had limited immediate utility, and was physically tiring to hold for extended interaction. P2 further suggested that adding contextual content (e.g., personally meaningful imagery), lighting, or interaction layers would increase experiential value. This negative case does not invalidate the thematic model; rather, it clarifies scope conditions. The current acrylic configuration reliably generates perceptual ambiguity and exploratory behaviour, but sustained engagement and perceived usefulness depend on ergonomic refinement and application framing.

8. Discussion

8.1 Ambiguity as Design Resource: Reframing “Low Resolution”

The dominant paradigm in display design treats visual ambiguity as a defect to be corrected through improved engineering. The qualitative field study challenges this assumption. The researcher entered with a “functionalist” mindset—framing the acrylic display against Retina/4K clarity standards—and expected complaints about blur. Instead, many responses were enthusiastic, physically engaged, and imaginative, while one clear negative case (P2) marked practical and ergonomic boundaries.

The acrylic display’s “low resolution”—its blur, distortion, and abstraction—functioned as a creative filter in at least three ways. First, it stimulated interpretive projection: because the image was not fully legible, participants filled in ambiguity with personal narratives drawn from their own cultural and experiential repertoires (magic shows, holograms, ghosts, sci-fi). The incomplete image became more engaging than a complete one would have been, because it invited active meaning-making rather than passive reception. Second, it avoided the uncanny valley: the cartoon-like abstraction of P2’s hand was experienced as playful precisely because it was clearly not a photorealistic rendering of human skin. The abstraction created aesthetic distance that made the self-representation feel safe and ludic rather than disturbing. Third, it generated curiosity and exploratory behaviour: participants were drawn to investigate the artefact—touching its surface, peering through it, holding it up to their own faces—rather than simply consuming what was displayed. The incompleteness of the image was a call to exploration.

The strongest evidence that low resolution is a feature rather than a defect came from P1: “Poor resolution is the specialty—if resolution improved the whole effect would be destroyed.” This statement directly supports the design argument: the floating depth illusion is not impaired by the material’s optical limitations but constituted by them. Increasing clarity—for example by changing wall thickness, slit spacing, or optical grade—would weaken the cues (refraction-induced displacement and selective occlusion) that generate the effect.

This finding has implications beyond the specific case of acrylic displays. It suggests that design strategies that deliberately calibrate the degree of ambiguity—rather than minimising it—may produce engagement qualities that high-fidelity systems cannot. The question is not “how clear can we make this?” but “what kind of ambiguity is productively engaging?”

8.2 Physical Synchronisation: Value as Emergent Phenomenon

A defining characteristic of the acrylic cross-section display is that perceptual value does not reside in the static artefact but emerges through active physical engagement. This is more than a technical constraint (viewing-angle dependency): it is a different viewer–medium relationship. The viewer must tilt the object or move their head to reveal and strengthen the floating image. Value is co-produced by material and body.

This transforms the acrylic display from a passive medium into an embodied interaction. The display is not a window through which content is observed but an instrument that rewards skilled, exploratory physical participation. Participants discovered this without instruction: P2 naturally began tilting the block; P4 held it up as a mask; P3 performed continuous head movements to modulate the depth percept. The affordances of the material—its weight, its reflective surface, its slit geometry—invited these behaviours without any explicit interface.

The motion-dependent depth cue provides the optical mechanism for this embodied affordance: different viewing angles produce different depth configurations, incentivising continuous movement. This creates a closed loop between physical action and perceptual reward—tilt the object, the image floats more strongly—without any electronic sensor, processor, or feedback system. The material itself is the interface. This positions the acrylic display within a growing body of HCI research on tangible and embodied interaction, but with the specific quality that the material generates the interaction affordances through its inherent optical properties rather than through engineered surface features.

8.3 Multiplicity of Interpretations: The Open Canvas and Cultural Frames

The divergence of participant interpretations is among the most theoretically significant findings of this study. P4, who identified as having a technical background, framed the artefact in technological terms: “Like a hologram.” P3 and P2, who approached the artefact more emotionally and imaginatively, reached for supernatural and performative metaphors: “I remember of the magic shows,” “Looking like a ghost.” P1 drew on perceptual and optical language: “more like a mirage,” “like multiple glass attached.” Despite observing the exact same physical phenomenon, the four participants produced four qualitatively different accounts.

This divergence is not measurement error—it is the display’s core expressive property. The acrylic display functions as an open canvas: ambiguity leaves interpretive space that viewers fill with their own frameworks. A fully clear, high-resolution image would constrain this openness.

The finding also carries a cultural dimension. P4’s “hologram” metaphor aligns with Japanese science-fiction media tropes, while P2’s “ghost” and P3’s “magic show” draw on different repertoires. The same material configuration thus supports culturally specific projections; this variability is a feature of an artefact that does not lock down a single reading.

Two additional framings sharpen this point. First, P2’s memory metaphor—“Our memories are also like this, all distorted, from every angle.”—casts the artefact as an externalised mnemonic medium rather than a display that should maximise legibility. Second, P2’s explicit “Photoshop filter” metaphor, alongside P4’s compatible framing of mediated perception, suggests that the artefact functions as expressive mediation: it does not replace perception, but layers an interpretive texture over it.

8.4 Researcher Positionality and the Interpretivist Shift

An important epistemological contribution is the transformation of the researcher’s stance during fieldwork. The researcher entered with an implicit positivist bias, evaluating the display against functional criteria. Participant responses forced a shift in question from “Can this serve as a screen?” to “What kinds of value emerge from this encounter?” This move from functionalist evaluation to interpretivist inquiry is itself a methodological finding.

This positionality shift is consistent with an axiology of curiosity and playfulness over efficiency. The initial assumption that “ambiguity equals defect” reflected an aesthetic of clarity that does not fit all display contexts. Field encounters reframed low resolution as a creative resource rather than a problem to be solved. This reflexive shift aligns with interpretivist principles and supports qualitative fieldwork as an appropriate method for exploratory design inquiry.

8.5 Implications for HCI Display Design

Taken together, these findings suggest five design principles for materiality-based displays in HCI:

1. Productive ambiguity: Intentionally calibrated visual ambiguity can enhance engagement when it opens interpretive space without entirely preventing functional use. Not all display contexts require maximum fidelity; some—particularly those oriented toward exploration, reflection, or play—may benefit from deliberate incompleteness.
2. Embodied affordance: Displays that reward physical engagement (tilting, moving, touching) create interaction modalities unavailable to fixed-frame screens, engaging the viewer’s body as a constitutive part of the interaction rather than a peripheral input device.
3. Material presence: The visibility of the display medium itself (the acrylic surface, its weight, its thickness, its reflections) creates an aesthetic that foregrounds materiality over technological transparency. This can be a feature rather than a limitation in contexts where the medium’s presence is expressive.
4. Interpretive openness: Displays designed to afford multiple interpretations—rather than enforcing a single reading—may be more appropriate in contexts where personal meaning-making, cultural diversity, and imaginative engagement are valued over information transmission efficiency.
5. Low-cost perceptual depth: Compelling depth experiences do not require expensive optical engineering—material thickness and simple geometric configurations can generate novel depth percepts accessible to monocular viewers and without wearable devices.

A practical illustration of these principles is the museum and gallery context. Displaying precious items through an acrylic cross-section display would transform conventional 2D image substitutes into engaging, motion-responsive perceptual experiences—without wearable devices, without the expense of engineering-intensive systems such as tensor displays or volumetric displays, and with the added quality of material presence where the display medium itself is visible and engaging. More broadly, any context where visitors, users, or audiences are expected to bring their own frameworks to bear on open-ended content—art installations, contemplative spaces, educational environments—might benefit from displays designed around interpretive openness rather than informational precision.

9. Evaluation through Theoretical Frameworks

9.1 Boden’s Framework: New, Surprising, Valuable

Boden defines creativity as “the ability to come up with ideas or artefacts that are new, surprising and valuable.” We evaluate this research against each criterion:

Newness: The shift from surface-based to edge-based optical exploration is novel in the autostereoscopic display literature. No prior work has systematically examined material cross-sections as display media for generating floating depth illusions.

Surprise: The floating depth illusion emerged serendipitously during preliminary exploration rather than being predicted through conventional engineering methods. More significantly, the qualitative field study produced multiple surprises: the diversity of participant metaphors overturned the researcher’s initial assumption that “there is one correct way to see this device”; the Transformation of Self theme (P4 wearing the acrylic as a face mask) was not anticipated; and participant-generated “filter” framings (most explicit in P2’s “Photoshop filter” metaphor) reframed the research premise.

Value: Practical value is demonstrated through the museum/gallery use case and the discovery of the floating depth illusion as a low-cost depth display mechanism. Theoretical value lies in the concepts of material intelligence as a design resource and interpretive openness as a display property, and in the demonstration that Creative Unintentional Use can surface design knowledge unavailable through conventional engineering methods.

9.2 Bridle’s Framework: Rethinking the Natural Order

Bridle observes that technology challenges “what we have foolishly come to think of as the natural order of things, demanding a radical rethinking of our worldview.” This research challenges two natural orders simultaneously:

Technological: The assumption that compelling 3D visual experiences require precision optical engineering and complex surface micro-structuring. The acrylic configuration demonstrates that simple material arrangements, without engineered surfaces, can generate depth percepts not achievable by conventional displays.

Experiential: The assumption that viewers are passive consumers of display content, and that display value resides in the static artefact. The physical synchronisation requirement transforms viewing into an active, embodied practice in which the viewer’s movement is itself part of the medium.

10. Limitations

This research is exploratory, and several limitations should be acknowledged across both strands.

10.1 Qualitative Field Study

Sample size and diversity. The field study comprised N = 4 participants. This is appropriate for initial phenomenological exploration but insufficient for theme saturation or generalisability. Additional participants may reveal metaphors, behaviours, and interpretive frameworks not captured here.

Demographic homogeneity. All participants were students in their 20s from a single institution (IIT Bombay), with design/engineering backgrounds. This likely biases responses toward novelty, technical interpretation (e.g., P4’s “hologram” framing), and a narrow cultural frame (three participants from India, one exchange student from Japan).

Cultural interpretive frames. Divergence between P4’s “hologram” and P2/P3’s “ghost”/“magic show” metaphors may reflect cultural imaginaries as much as individual cognition. The current design cannot disentangle these factors. IIT Bombay’s specific campus culture may also limit transferability.

Researcher positionality and single-analyst coding. The researcher designed the artefact, conducted interviews, and performed coding. No second analyst, inter-rater reliability measure, or member checking was used, increasing risk of interpretive bias in theme construction and quote selection.

Session structure and presentation effects. All sessions were run by the artefact designer. Researcher enthusiasm may have introduced social desirability effects. In addition, presentation was not fully standardised: ordering and framing (including whether the object was framed as a “display”) varied across participants.

Single-session, non-longitudinal design. All interactions were first encounters. Effects of repeated exposure are unknown: novelty may decay, or deeper engagement may emerge. No longitudinal data were collected.

10.2 Physical Design and Ergonomic Constraints

Weight and handling ergonomics. The current prototype is a solid acrylic block with non-trivial weight and volume. P2 noted fatigue during sustained handling. This constrains deployment where users must hold/tilt the artefact for extended periods and raises accessibility concerns for users with reduced grip strength or mobility. Fatigue and ergonomic comfort were not systematically measured.

Interaction legibility. P3 stated that the intended interaction was not self-evident: “I don’t know what it is supposed to be unless someone tells me.” Affordances may emerge through exploration, but not immediately. Without orientation or signage, users may miss the tilt interaction and experience the artefact as an opaque block.

10.3 Design Research Investigation

Uncontrolled material parameters. The field study used one configuration (1 mm slit spacing, 2 mm thickness). Reported perceptions therefore reflect a single condition, not the full design space. Effects of thickness, spacing, finish, and clarity cannot be isolated.

Lack of quantification. Optical mechanisms were characterised qualitatively, but perceived depth magnitude, viewing-angle thresholds, and luminance contrast ratios were not measured. Effects of slit spacing and acrylic grade remain unquantified.

Informal observational conditions. Sessions were conducted in uncontrolled ambient lighting. Because the floating effect is lighting-sensitive, observations across sessions are not strictly comparable.

10.4 Integrated Methodology

Combining design research and qualitative inquiry in one study means neither strand reaches the depth of a dedicated investigation. The optical strand is not yet systematic enough for quantitative design guidelines, and the qualitative strand is not large enough for theoretical saturation. The combination is productive for initial exploration, but each strand needs follow-up with stricter protocols.

11. Future Work

This study establishes an initial two-strand foundation. The next phase should prioritise a smaller set of high-impact directions.

11.1 Qualitative and User Research

Expanded and diversified field study. The first priority is larger and more diverse sampling across age, discipline, cultural background, and technology familiarity. A cross-cultural comparison can test whether metaphor divergence (e.g., “hologram” vs. “ghost”) reflects systematic cultural differences or individual variation.

Longitudinal study. A second priority is repeated-exposure research to test whether novelty decays or deeper perceptual layers emerge over time, especially in settings with returning visitors.

Protocol and analytic rigour. Future studies should use standardised presentation, second-analyst coding, and member checking. Targeted negative-case sampling would further clarify boundaries of the current thematic model.

11.2 Optical and Material Research

Systematic parameter study. Controlled variation of slit spacing (0.5–3 mm), thickness (1–5 mm), finish (polished/matte/frosted), and clarity should establish quantitative links to depth magnitude, angle threshold, and contrast.

Perceptual and photometric validation. Psychophysical experiments (e.g., N ≥ 20) and luminance measurements should validate robustness across viewers and explain which parameter combinations produce stronger floating effects.

11.3 Application Prototyping

Deployment-oriented prototype. A functional prototype should be tested in museum/gallery contexts, evaluating engagement, accessibility, durability, and integration with existing display infrastructure.

Targeted application tracks. Two focused tracks are recommended: (1) self-representation/performance uses suggested by the Transformation of Self finding, and (2) larger-format projection uses suggested by participant feedback and “complete screen” observations at oblique angles.

11.4 Theoretical Development

Focused theoretical agenda. Theoretical work should prioritise two constructs: material intelligence as a design framework and interpretive openness as a calibratable design quality. These should be developed in parallel with empirical studies rather than as standalone conceptual expansion.

12. Conclusion

This paper presented “The Unintended Edge,” combining Creative Unintentional Use with an interpretivist qualitative field study to examine how digital natives perceive and engage with acrylic cross-section displays.

The design research investigation characterised the floating depth illusion in the linear slit configuration: refraction through material thickness combined with selective occlusion by acrylic walls generates monocular depth cues through viewer movement, without any engineered surface features.

The qualitative field study (N = 4) yielded a thematic model organised around four interconnected themes: Synced Movement (physical engagement as prerequisite for the perceptual experience), The Floating Image (depth perception distinct from flat screens, interpreted as hologram, mirage, or 3D glass effect), Transformation of Self (reinterpretation of one’s own body through the material, including cartoon-like and non-human body perception), and Magic & Play (projection of supernatural and performative narratives onto visual ambiguity). Participants’ divergent metaphors demonstrate that the acrylic display functions as an open canvas that stimulates personal narrative rather than imposing a single reading.

Three cross-cutting insights extend beyond the thematic model. First, P1 stated that “poor resolution is the specialty: if resolution improved, the whole effect would be destroyed,” supporting the claim that degradation is mechanism, not flaw. Second, P2 framed distortion as analogous to memory—“our memories are also like this, all distorted, from every angle”—opening directions for memory-related and archival applications. Third, P3 refused the screen categorisation—“I see it as a material, not as a screen”—supporting the Material-Driven Design framing from the user side.

Together, these findings argue that ambiguity, material presence, and embodied affordance are productive resources in HCI display design—qualities often absent in precision-engineered, high-fidelity displays. The acrylic edge’s “low resolution” is not a defect to correct; it stimulates imagination, invites embodied exploration, and affords multiple interpretations across cultural and disciplinary backgrounds. In this sense, the unintended edge is the most important edge.

Acknowledgments

I thank my supervisor, Prof. Sugandh Malhotra, for supervision and guidance throughout this research, and Prof. Kanika Jolly and Prof. Yohan Engineer for critical feedback that substantially improved both the optical investigation methodology and the qualitative research design. I also thank the four participants who generously gave their time, curiosity, and candid reflections during the field study. This work was conducted at IDC School of Design, IIT Bombay.

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