Threshold / Implementation studies

Selected frontend code.

Three implementations from my AI-assisted projects: React motion, editor state and responsive 3D framing. Each connects an interaction to the code, its tests and my contribution.

01 / Tablebound · React / animation / accessibility

Motion that presents the saved result.

A React dice-result component turns a recorded value into a brief visual reveal. The animation never determines the result.

DiceResult.tsx Formatted excerpt · original lines 13–20
useEffect(() => {    setExpanded(false);    let frame = 0;    const media = window.matchMedia('(prefers-reduced-motion: reduce)'), start = performance.now();    const finish = () => {        cancelAnimationFrame(frame);        setAnimation({ id: event.id, progress: 1 });    };    const animate = (now: number) => {        const t = Math.min(1, (now - start) / 1100);        setAnimation({ id: event.id, progress: 1 - (1 - t) ** 3 });        if (t < 1)            frame = requestAnimationFrame(animate);    };    if (media.matches || !rolls.length)        finish();    else {        setAnimation({ id: event.id, progress: 0 });        frame = requestAnimationFrame(animate);    }    const change = () => {        if (media.matches)            finish();    };    media.addEventListener('change', change);    return () => {        cancelAnimationFrame(frame);        media.removeEventListener('change', change);    };}, [event.id]);

The decision

Animation belongs to presentation, not game authority. The component resolves directly to the saved value, honors reduced motion, and retires frame callbacks when the event changes or the component unmounts.

Verification & scope

Six existing geometry tests passed, covering d4, d6, d8, d10, d12 and d20. Browser checks of the isolated original component cover replay, reduced motion and inspection without auto-dismissal.

Try the original component

A fixed sample result, rendered by the existing React component. No account or AI request.

Open study on its own ↗

Tradeoff. The excerpt is the animation effect inside DiceResult; state and drawing are in the full component. The geometry uses a lightweight projection, not a physical dice simulation.

Original full source ↓Original test excerpt ↓Project context ↗

02 / LuminaCut Studio / V2 editor · TypeScript / React state / editing UX

One gesture. One undo.

A continuous slider movement should undo as one editing decision. Moving the playhead should leave the edit history alone.

store.ts Formatted excerpt · original lines 73–87
function commit(state: EditorState, project: ProjectSnapshotV2, notice: string, selection = state.selectedItemIds, coalesceKey?: string): EditorState {    if (project === state.project)        return { ...state, notice };    const now = Date.now();    const coalescing = Boolean(coalesceKey && state.lastCoalesce?.key === coalesceKey && now - state.lastCoalesce.timestamp < 900);    return {        ...state,        project,        selectedItemIds: selection,        history: coalescing ? state.history : [...state.history.slice(-99), state.project],        future: [],        lastCoalesce: coalesceKey ? { key: coalesceKey, timestamp: now } : undefined,        dirty: true,        notice,    };}

The decision

The editor reducer records committed project snapshots and coalesces consecutive changes with the same gesture key. Transient playback and selection state stay outside that history.

Verification & scope

Three existing reducer tests passed: undo/redo without playhead history, continuous slider coalescing, and protection against an older autosave response.

Try the original reducer

Scale a sample clip, undo the change, then move the playhead. The existing editor state runs unchanged in a small portfolio view.

Open study on its own ↗

Tradeoff. History keeps up to 100 project snapshots. The 900 ms coalescing window is a time-based heuristic. This source belongs to the React V2 editor; the main studio URL opens the earlier JavaScript editor.

Original full source ↓Original test source ↓Project context ↗

03 / Walter Newsroom V2 · TypeScript / Three.js / responsive composition

Reframe the story for a narrow screen.

Desktop can show the host and evidence together. A narrow viewport needs deliberate framing so the supporting material remains legible.

director.ts Formatted excerpt · original lines 5–19
/** Fit the subject horizontally without moving a camera outside the spacecraft. */export function fitFov(width: number, height: number, distance: number, aspect: number) {    return Math.min(112, Math.max(24, 2 * Math.atan(Math.max(height, width / aspect) / (2 * distance)) * 180 / Math.PI));}export function portraitFrame(shot: Shot, aspect: number, side: EvidenceSide = 'visual', flagship = false): Framing {    if (shot === 'story') {        const x = side === 'visual' ? -1.74 : 1.74;        return {            position: [x, 1.7, 1.78], target: [x, 1.67, -.32], fov: fitFov(1.49, side === 'visual' ? 1.05 : 1.65, 2.10, aspect)        };    }    if (flagship && shot === 'close')        return {            position: [.035, 1.72, 1.05], target: [.085, 1.695, .025], fov: fitFov(.57, .57, 1.025, aspect)        };    if (flagship && shot === 'medium')        return {            position: [.025, 1.76, 1.90], target: [.065, 1.48, .02], fov: fitFov(.92, 1.18, 1.88, aspect)        };    if (shot === 'close')        return {            position: [0, 1.72, 1.03], target: [0, 1.685, .015], fov: fitFov(.39, .51, 1.02, aspect)        };    if (shot === 'medium')        return {            position: [0, 1.77, 2.45], target: [0, 1.40, .02], fov: fitFov(1.16, 1.48, 2.44, aspect)        };    return {        position: [0, 1.86, 4.20], target: [0, 1.53, -.22], fov: fitFov(5.15, 3.1, 4.42, aspect)    };}

The decision

Camera field of view is fitted to the subject dimensions and viewport aspect ratio. Portrait-specific positions keep the camera inside the ship; editorial logic preserves explicitly locked cues.

Verification & scope

Both existing director tests passed: complete hologram framing at three portrait ratios, and explanation inserts that preserve locked cues and desktop behavior.

Tradeoff. Camera positions are authored for this particular set. Field of view is bounded; this is a scene-specific directing rule rather than a general responsive layout engine.

Original full source ↓Original test source ↓Project context ↗

Source & contribution notes

The excerpts are selected from the existing project files. Display formatting adds indentation and syntax color; downloads preserve the originals. The studies make a focused behavior inspectable rather than claiming the entire application is production-certified.

AI tools assisted implementation and debugging. Maxwell’s contribution covers concept, interaction and visual direction, working-build evaluation and iteration. These are independent projects, not work commissioned by Amazon.

Earlier implementation excerpts & provenance

The previous playback controller, transcript-review component and navigation helpers remain available as supplementary files.

Playback controller · Transcript review · World navigation

Original-file fingerprints and source ranges are recorded in the provenance record. The isolated motion study includes dependency licenses.

The undo study uses the original reducer and core source with a separate portfolio harness. The still image is a fixture; the study does not import, render or export a video.