Kimi K3 · HTML Files

Build a playable, cinematic single-page Three.js experience: a small boat drifting through a Norwegian-style fjord / coastal mountain landscape.

Requirements:
- ONE self-contained index.html file (HTML + CSS + JS inline). No external assets of any kind (no textures, models, fonts, audio files) EXCEPT Three.js itself, loaded via an import map from this exact pinned CDN:
  "three": "https://cdn.jsdelivr.net/npm/three@0.160.0/build/three.module.js",
  "three/addons/": "https://cdn.jsdelivr.net/npm/three@0.160.0/examples/jsm/"
  All textures (water normals, rock, snow, bark, clouds, etc.) must be generated procedurally in code (canvas / DataTexture / shaders).
- Scene content: steep procedural fjord walls and mountains with snow caps, rock and grass coloring by height/slope; procedural conifer forests (instanced); a water surface with animated waves and sky/landscape reflections; a lighthouse on a rocky point with a rotating beam that matters at night; a small wooden boat with 2 simple stylized 3D characters on it (one rowing/steering, one looking around, with small idle animations); distant islands; birds or other small life if cheap.
- Dynamic weather cycling clear -> fog -> rain -> storm -> clearing, with smooth transitions: fog density, cloud cover, rain particles, lightning flashes + wind and bigger waves in the storm.
- A full day/night cycle: sunrise, day, golden hour, sunset, night with stars and moon, lit lighthouse and boat lantern. Sky color, sun/moon lights, and fog color must track time of day.
- Controls: keyboard (WASD/arrows to steer and throttle the boat, C to switch camera, T toggles auto-tour, 1-5 to force weather, N to jump time) and touch (on-screen joystick/buttons on phones). Camera follows the boat in play mode.
- An "auto-tour" cinematic camera mode: slow, smooth, film-like camera moves (orbits, low water-level glides, high establishing shots, close-ups of the characters) while the boat drifts along a path through the fjord and the weather and time of day progress.
- Minimal, elegant UI: small title "Fjordlys" (or a better name of your choice), a tiny hint line for controls, fading out in tour mode.
- Must run smoothly on desktop and phone browsers: keep geometry/particle counts moderate, cap devicePixelRatio at 2, handle resize/orientation.
- IMPORTANT for automated video capture, support these URL parameters:
  ?tour=1        start directly in auto-tour mode
  ?capture=1     hide ALL UI overlays (title, hints, touch controls)
  ?cycle=40      when present, compress one complete showcase into that many seconds: the time of day goes from morning through golden hour, sunset and night, and the weather passes clear -> fog -> rain -> storm -> clearing within that span (so a 40-second recording shows everything). Without it, use a relaxed pace suited to live play.
  Drive all animation from the requestAnimationFrame timestamp / performance.now() (not from wall-clock-independent accumulators that ignore time), so that overriding those functions steps the scene deterministically. Set window.__sceneReady = true once the first frame has rendered.
- No console errors or warnings in a current Chrome. Use modern Three.js r160 APIs only (no deprecated/removed ones).

Output ONLY the complete index.html, starting with <!DOCTYPE html> and ending with </html>, with no explanation and no markdown fences. Build it as index.html (plus any local asset files you create) in the current directory. Three.js may load from a pinned CDN. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own until it looks genuinely cinematic before finishing. Close any browser you open as soon as you've taken your screenshot.

Write a single self-contained HTML file that plays an original animated short film, about 50 seconds long, drawn entirely in code.

Hard technical rules:
- One file: HTML + inline <script> (+ optional inline <style>). No external images, fonts, libraries, audio files or network requests of any kind. Every frame is drawn procedurally with Canvas 2D (or WebGL if you prefer).
- The canvas renders at a fixed internal resolution of 1920x1080 and is scaled with CSS to fit the window (letterboxed, black background).
- The animation starts automatically on page load and is driven ONLY by requestAnimationFrame and the timestamp from performance.now() (measure elapsed time from the first frame). Everything on screen must be a pure function of elapsed time t, so the film is deterministic and can be captured frame by frame. No Math.random() at draw time — use a seeded PRNG / hash noise so frames are identical run to run. No setTimeout/setInterval for animation.
- Define window.FILM_DURATION (seconds). After the film ends, hold the final frame.
- Soundtrack: write an original WebAudio score (melody, chords, a little percussion or ambience, and sound cues that match story moments) synced to the same timeline. Put ALL audio scheduling in a function window.buildSoundtrack(ctx, startTime) that schedules every note/effect on any BaseAudioContext (so it also works on an OfflineAudioContext). Also expose window.renderSoundtrack = () => an OfflineAudioContext(2, 44100*FILM_DURATION, 44100) render of it returning a Promise<AudioBuffer>. For live viewing, start the soundtrack on the first click/tap/keypress (browsers block autoplay) aligned to the current film time; show a small unobtrusive "tap for sound" hint until then. Use only oscillators, noise buffers you generate, filters, gain envelopes — no samples.
- No console errors.

The film (this is a showcase of what you can animate — make it genuinely beautiful and moving):
- An ORIGINAL story with a small emotional arc (setup, a problem or longing, a turn, a warm resolution). A single consistent main character — any character you like — who appears in every scene and is recognisably the same design throughout.
- At least 4 distinct scenes, with real transitions between them (e.g. wipes, iris, match cuts, cross-dissolves, camera moves through space).
- Expressive character animation: a proper walk cycle (legs, arms, body bob), blinking, and facial emotion changes (e.g. curious, sad, surprised, joyful) that follow the story.
- A virtual camera that pans, zooms and tracks, with parallax layers for depth.
- Lighting and time-of-day changes across the film (e.g. dawn → day → dusk → night, or a storm clearing), with colour grading, glows, and shadows.
- Particles and weather (rain, snow, fireflies, leaves, dust, stars — your choice, at least two kinds).
- On-screen story text / subtitles in a tasteful storybook style that tell the story in a few short lines.
- A cohesive art direction: a warm, hand-made "paper cut-out / storybook" look is welcome (textured paper, soft edges, slight wobble), but choose what serves your story.
- End with a title of your film and a gentle closing frame.

Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>. No explanation, no markdown fences. Save it as index.html in the current directory. You may open it in headless chromium to check it and iterate.

ok here it is - my first Opus 5.5 vibecoded threejs 3D experience

my God!! Opus is creative!!

I made a road that forgets which way is down.

It folds 90° up a yellow wall, runs upside down across a ceiling, and turns into sheet music: steer through the notes to play each street's melody.

Watercolour. Ink. A radio on the roof.

#vibejam Build it as index.html (plus any local asset files you create) in the current directory. Three.js may load from a pinned CDN. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own before finishing. Close any browser you open as soon as you've taken your screenshot.

Build a GPU-accelerated fluid simulation in a single HTML file using WebGL, no external libraries. Dragging the mouse or a finger should push colorful dye through the fluid, with a soft glow. Make it look stunning and run smoothly.

Build it as a self-contained index.html in the current directory, with WebGL/WebGL2 shaders you write yourself; no libraries and no CDNs; interactive with mouse or touch input. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own before finishing. Close any browser you open as soon as you've taken your screenshot.

Build a small playable 3D game in Three.js: an ant defends its home from a furious giant gardener. The player controls the ant on the ground of a lush garden, seen from a low third-person camera that makes the grass blades, pebbles and flowers feel huge. The gardener towers over the scene and sweeps a humming string trimmer back and forth, chasing the ant and throwing up clippings. The ant fights back with a tiny slingshot: aim with the mouse, fire pebbles at the gardener and dodge the trimmer's swings. Show a health bar for the ant and a large health bar for the gardener at the top of the screen, with hit flashes, a clear win or lose message and a restart. Warm afternoon sunlight falls through the leaves overhead, casting moving dappled light and soft shadows, with dust drifting in the light beams. Keep the controls simple (WASD or arrow keys to move, click to shoot) and show them on screen. Everything is built in code from Three.js geometry and materials; no external models or textures. Build it as index.html (plus any local asset files you create) in the current directory. Three.js may load from a pinned CDN. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own before finishing. Close any browser you open as soon as you've taken your screenshot.

# Test: threejs_artwork_style_pass

Build a real-time 3D scene in three.js: a **caped flying hero** flies through a row of **large framed artworks**, and each time he passes through a frame **his rendering style changes to match that artwork's style**.

- The hero is an original, generic caped flyer (your own design, not any existing or trademarked character): a stylised humanoid in a flying pose, fists forward, with a cape that flutters and ripples in the wind as he flies.
- A row of at least **five big picture frames** stands along his flight path, spaced out, each with a gilded frame and a procedurally generated canvas in a different style, for example: **oil painting** (thick brush strokes), **ukiyo-e woodblock** (flat colours, bold outlines, wave pattern), **pixel art**, **comic book / halftone** (dots, ink outlines), **watercolour** (soft bleeding washes). More styles are welcome.
- As he flies **through** each frame, the hero's look switches to that artwork's style (custom shaders / materials / post-processing, e.g. toon shading + outlines, halftone dots, pixelation, painterly noise, paper texture), ideally with a short visible transition at the moment he crosses the frame plane. Optionally the world around him can also take on the style.
- Motion must be **smooth and continuous** (no teleporting or snapping): he flies along a gentle curved path through all frames, and the whole sequence loops seamlessly.
- The **camera follows** him smoothly (chase camera with slight lag), keeping both the hero and the next frame in view.
- Good lighting, sky/background and atmosphere; aim for a polished, showcase-quality look.


Deliverable: reply with exactly one complete, self-contained `index.html` file in a single ```html code block. Requirements:
- Use three.js (r160 or newer) loaded from a CDN through an `<script type="importmap">` (e.g. jsDelivr or unpkg); addons such as OrbitControls may be imported from the same CDN via the import map.
- No other files: no external textures, models, fonts or images. Generate any textures procedurally in code.
- It must run by simply opening index.html in a modern desktop browser, fill the window, and handle resize.
- Animate with requestAnimationFrame and a clock, so it looks right at any frame rate.
- No explanation is needed outside the code block.

Build a single self-contained Three.js scene of a fantasy sailing ship at sea, seen from a cinematic three-quarter view. The ship has a carved dragon figurehead at the bow with an open jaw and horns, a wooden hull with visible planking and a raised stern castle, three masts with full canvas sails that billow and a few pennants, rigging lines, and lanterns along the rail. It sails on animated water with rolling waves, foam at the bow, reflections and a sun path on the surface. Behind it a rocky coast with a small harbour town: stone houses with tiled roofs, a lighthouse, a pier and scattered trees on green hills. Warm late-afternoon lighting with a low sun, long shadows, light haze in the distance and a sky with a few clouds. The camera slowly orbits the ship. Everything is built in code from Three.js geometry and materials; no external models or textures.

Output ONLY the complete index.html, starting with <!DOCTYPE html> and ending with </html>, with no explanation and no markdown fences. Build it as index.html (plus any local asset files you create) in the current directory. Three.js may load from a pinned CDN. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own until it looks genuinely cinematic before finishing. Close any browser you open as soon as you've taken your screenshot.

# Test: threejs_mechanical_bee

Build a real-time 3D scene in three.js of an animated **mechanical (clockwork) bee**.

- The bee is built from many distinct parts: a segmented abdomen, thorax, head with compound-eye lenses, antennae, six jointed legs and two pairs of wings.
- Materials are physically based (MeshStandardMaterial or MeshPhysicalMaterial): polished and aged **brass**, brushed **steel**, a little dark enamel or glass, with believable metalness/roughness. Use an environment map (e.g. RoomEnvironment with PMREMGenerator) so the metal reflects.
- The **wings beat fast** (a visible blur-like flutter, thin translucent panels with a metal frame/veins).
- Several visible **gears turn** inside the body (meshing gears turn in opposite directions at speeds consistent with their tooth counts).
- The whole bee **hovers with a gentle bob and slight sway loop** in mid-air; legs and antennae move a little.
- **OrbitControls** let the viewer orbit, zoom and pan around the bee, with damping.
- **Nice lighting**: a key light with soft shadows, a fill and a rim light, tone mapping (ACES or AgX) and sRGB output; a tasteful backdrop or ground so the shadow reads.
- Aim for a polished, showcase-quality look.


Deliverable: reply with exactly one complete, self-contained `index.html` file in a single ```html code block. Requirements:
- Use three.js (r160 or newer) loaded from a CDN through an `<script type="importmap">` (e.g. jsDelivr or unpkg); addons such as OrbitControls may be imported from the same CDN via the import map.
- No other files: no external textures, models, fonts or images. Generate any textures procedurally in code.
- It must run by simply opening index.html in a modern desktop browser, fill the window, and handle resize.
- Animate with requestAnimationFrame and a clock, so it looks right at any frame rate.
- No explanation is needed outside the code block.

Build a complete, polished mobile-first 3D arcade game in Three.js as one self-contained index.html (no external assets; all geometry, textures and sound procedural). Portrait orientation, touch controls (swipe/drag and tap) with keyboard fallback for desktop. Include a title screen, at least 3 increasing difficulty phases, score and best-score persistence in localStorage, juicy feedback (screen shake, particles, procedural Web Audio sfx), pause/resume when the tab is hidden, and a game-over screen with restart. Must hold 60 fps on a mid-range phone; keep draw calls low with instancing.

Build a conceptual X-16 engine in 3D with Three.js: four cylinder banks, one crankshaft and exposed mechanics inspired by experimental multi-bank engine architectures. Make it animate (pistons, rods and crank moving in sync) with orbit controls. Everything is built in code from Three.js geometry, shaders and materials; no external models or textures. Build it as a single self-contained index.html in the current directory. Three.js may load from a CDN or be vendored. You may serve it locally and open it in headless chromium (/usr/bin/chromium, software WebGL, no GPU) to screenshot and inspect your own output, and iterate on your own before finishing. Close any browser you open as soon as you've taken your screenshot.

Ink Bloom Garden: A dark canvas where every click plants an ink-drop flower that grows outward in branching, feathered petals over three seconds using layered translucent strokes. Petal colour drifts with the mouse's horizontal position. Space clears the canvas with a slow fade; S saves the current canvas as a PNG.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Pendulum Wave: Fifteen pendulums hung side by side, each with a slightly different period so that together they form travelling waves, snakes and brief alignments that repeat every 60 seconds. Show a slider for playback speed, a reset button, and draw a faint trail behind each bob.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Orbital Coffee Landing: A landing page for an invented specialty coffee roaster: a full-height hero with a CSS-drawn steaming cup, three origin cards that tilt in 3D toward the cursor, a scroll-triggered brew timeline, and a sticky header that shrinks after 80px of scrolling. Fully responsive down to 360px.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Brick Breaker Neon: A neon brick-breaker: a paddle follows the mouse or arrow keys, the ball bounces off six rows of glowing bricks, and destroyed bricks burst into particles. Include three lives, a score, a level-two layout after clearing, a pause on P, and a game-over screen with restart.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Focus Timer Orbit: A focus-session timer drawn as a planet orbiting a sun: a full orbit equals the session length. It supports 25/5 work/break cycles with editable durations, start/pause/reset, a counter of completed sessions, and a soft synthesised chime at each transition generated with WebAudio.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Rainfall Bars: An animated bar chart of monthly rainfall for an invented city (Jan 78mm, Feb 64, Mar 55, Apr 40, May 22, Jun 10, Jul 8, Aug 12, Sep 30, Oct 52, Nov 70, Dec 85). Bars fill like rain gauges, hovering shows a tooltip, and a toggle switches between millimetres and inches.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Kinetic Headline: The phrase MAKE SOMETHING WEIRD in huge letters, where each letter is an independent element that scatters away from the cursor on a spring and eases back home. Clicking cycles through three typefaces from generic font families; letters wobble slightly while idle.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Pocket Theremin: A full-screen theremin: horizontal mouse position sets pitch across two octaves on a pentatonic scale, vertical position sets volume and vibrato depth. Holding the mouse down plays a WebAudio oscillator; a glowing trail and a live waveform display follow the pointer. Keys 1-4 switch waveform.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Forest Fire Automaton: A cellular-automaton forest on a 150x100 grid: trees regrow with probability p, lightning strikes with probability f, and fire spreads to neighbours. Sliders adjust p and f live, a counter shows live trees, burning cells glow orange to red, and a click drops a spark.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Toggle Switch Gallery: A gallery of eight distinct toggle switch designs on a neutral grid: day/night, liquid blob, rocker, pill with icon, 3D push, checkbox morph, skeuomorphic lever and minimalist line. Each animates smoothly between states, is keyboard accessible, and shows its current state label underneath.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Pure CSS Sunset: A layered sunset over rolling hills built entirely with CSS gradients, shapes and keyframe animation, with no canvas or script: the sun sinks over 20 seconds, the sky shifts from gold to violet, stars fade in, and a small silhouetted windmill turns on a hill.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Magnetic Filings: Thousands of short iron-filing strokes on a pale background align to the field of two draggable magnets, one red north and one blue south. Strokes recompute live as magnets are dragged; a double click adds a third magnet and a button flips each polarity.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Soft Body Blobs: Five jelly-like blobs made of spring-connected points fall into a box, squish on impact and jostle each other. The user can grab and fling any blob with the mouse. A gravity slider and a button that tilts the box left or right are included.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Snake Reimagined: A modern snake game on a 24x24 grid with smooth interpolated movement, a gradient body that tapers to the tail, food that pulses, and walls that wrap. Speed increases every five apples. Show score and best score (saved in localStorage) and support arrows, WASD and swipe.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Color Palette Studio: A palette generator: press space to generate five harmonious colours (choose analogous, complementary, triadic or monochrome), click a swatch to lock it, and show each colour's HEX, RGB and a WCAG contrast rating against white and black. Clicking a code copies it with a toast.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Heartbeat Line: A live ECG-style monitor that scrolls a heartbeat trace across a dark grid, with a BPM readout, a slider from 40 to 180 BPM that changes the rhythm in real time, a red flash on each beat, and an optional synthesised beep per beat.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Typewriter Poem: A vintage typewriter page that types out a short original eight-line poem character by character with slight timing randomness, ink density variation and occasional struck-through corrections. Each keystroke plays a synthesised click, a bell rings at each line end, and a replay button restarts it.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Step Sequencer Grid: A 16-step, 8-row drum and synth sequencer with a lit grid. Kick, snare, hat and clap are synthesised with WebAudio, plus four pentatonic notes. Includes a tempo slider (60-180 BPM), a moving playhead, clear and randomise buttons, and swing control.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Boids Lagoon: A school of 200 fish following boids rules (separation, alignment, cohesion) in a teal lagoon, drawn as small tapered shapes that flex as they turn. Moving the mouse introduces a predator they flee from; sliders tune the three weights and a counter shows the FPS.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Pricing Table Trio: A three-tier pricing section for an invented design app: monthly/annual toggle that animates the prices with a 20% discount, a highlighted middle plan with a ribbon, feature lists with check and cross icons, and hover states that lift cards. Responsive stacking on mobile.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Rotating CSS Cube: A 3D cube built purely with CSS transforms, each face a different gradient pattern with a label, rotating continuously on two axes. Hovering pauses it and a row of six buttons snaps it smoothly to show a chosen face. No JavaScript except the buttons.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Mandala Painter: A radial drawing tool: whatever the user draws with the mouse is mirrored across N rotational segments (slider from 3 to 24) with optional reflection, producing a live mandala. Include a brush size control, a colour picker, an undo button and a clear button.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Mortgage Calculator: A clean mortgage calculator: inputs for price, deposit, interest rate and term. It shows the monthly payment, total interest, and an animated donut of principal versus interest, plus a scrollable amortisation table by year. Every value updates live as sliders move.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Tower Stack: A one-button stacking game: a block slides back and forth above a growing tower; clicking or pressing space drops it, and any overhang is sliced off and falls away. Colours shift with height, the camera rises smoothly, and a perfect drop gives a bonus combo.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.

Gravity Well: An n-body toy: click and drag to launch planets with a velocity arrow into a system with one massive star. Bodies attract each other and leave fading orbit trails, collisions merge masses, and buttons reset the system or load a stable three-planet preset.

Build it as ONE self-contained HTML file: inline CSS and JavaScript only, no libraries or frameworks, and no external requests of any kind (no CDNs, web fonts, images or audio files); anything visual or audible is made in code (HTML/CSS, SVG, Canvas, WebGL or WebAudio). It must work when opened directly from disk, fit the browser window responsively, and run without console errors. Output ONLY the complete HTML file, starting with <!DOCTYPE html> and ending with </html>, with no explanation or markdown fences.