Opus 5.5 Build Day

Make a sixty-second short film that plays live in the browser with no video, images or fonts: every pixel comes from one WebGL2 fragment shader. The scene is the Golden Gate at dusk, seen from the Bay: raymarch the ocean, the two towers, deck and main cables as signed distance fields, the headlands behind, and thick fog rolling through the Gate, driven by animated 3D noise. Choreograph the camera: start low on the water, rise past a tower, end wide as the sun sets, the sky turns deep blue and the bridge lights come on. Add film grain, a 2.39:1 letterbox, a title card and closing credits drawn with canvas text, a Web Audio foghorn and wave wash, then loop. Tap or click starts it, space pauses, a thin scrubber along the bottom, F for fullscreen. Hold 60 fps by rendering at a lower internal resolution and scaling up when frames run long. No lens flares, no purple gradients, no emoji. Done means it opens to the title card with zero console errors or shader warnings and loops on a laptop and a phone. One self-contained HTML file, no external libraries or assets.

Build a complete, playable chess game with its own engine. Implement full legal move generation: castling, en passant, promotion with a piece picker, check, checkmate, stalemate, threefold repetition and the fifty-move rule. The engine is iterative-deepening alpha-beta with quiescence and move ordering, material plus piece-square evaluation, running in a Web Worker made from an inline Blob so the board never freezes, one second per move. On boot, run a perft self-test from the starting position and show a table for depths 1 to 4 with computed and expected node counts (20, 400, 8902, 197281); each row turns green when it matches, and the game unlocks when all four pass. UI: a board that fills the screen, pieces drawn as vector shapes, tap or drag to move with legal squares highlighted, an evaluation bar, the engine's principal variation and depth in large type, buttons for new game, flip, undo and my colour. Warm wood and cream palette, no glass panels, no pill buttons. Done means it opens straight to a playable board at 60 fps with zero console errors and works with touch on a phone. Single self-contained HTML file, no external libraries or assets.

Create a heart-rate monitor that uses only the camera. Two modes: face mode, where I line my face up inside an oval on the mirrored preview and you average the green channel inside it; and fingertip mode, where a finger covers the camera and you use the frame's red channel. Keep a twenty-second sliding window, detrend with a moving average, band-pass to 0.7 to 3 Hz, and estimate beats per minute from the dominant spectral peak, with confidence from its signal-to-noise ratio. Show the BPM in digits readable across a room, a scrolling waveform of the filtered signal, the spectrum with its peak marked, a heart that pulses on each beat, and a message while the signal settles. A big Start button opens the camera, the preview video is muted and inline, cameras switch front and rear, and it works on a phone in portrait. No gradients, no glass panels, no emoji. Done means it opens straight to the Start button, a 60 fps interface, zero console errors, a steady reading within fifteen seconds when I hold still in room light, and a clear message if the camera is denied. One self-contained HTML file, no external libraries or assets.

Make a one-button arcade game: a San Francisco cable car climbing California Street. The hill is procedurally generated from summed sines; the car has mass and rolls with gravity and friction. Holding the button (space, click or touch) grips the cable, which pulls the car at a constant 9.5 mph; releasing coasts. Passengers wait at stops: halt inside the stop zone to pick them up, bell and score; overshoot and they wave you off. Fog and Victorian houses in parallax, flat Canvas 2D shapes. Synthesize the bell, cable hum and brake screech with Web Audio. Big score and speed readouts, a start screen, game over after three missed passengers, best score in localStorage. No pixel-art fonts, no neon glows. Done means it boots to the start screen at 60 fps with zero console errors and plays with touch on a phone. Single self-contained HTML file, no external libraries or assets.