Claude explains how it was built:
It's built with Vite and TypeScript, as nine scenes on one 3-minute timeline. Every frame, a 2D canvas redraws each pencil stroke from scratch as several slightly offset, wobbly passes. These are re-randomized 12 times a second, so the lines shimmer like hand-drawn animation. A WebGL shader then adds paper texture, grain, a vignette, subtle chromatic aberration, and heat haze that grows as the story gets hotter. The charts plot real data: JMA summer temperatures back to 1898, plus 2026 records from JMA releases and news reports.
There are no recordings at all. Every sound is synthesized live in the browser. The koto is a plucked-string simulation, the wind chimes use FM synthesis, and the flute, shō and taiko are built from oscillators and noise. Cicadas, rain and wind are filtered noise, and even the reverb is generated. The music plays from a written score, and the audio clock drives the animation, so sound and picture stay in sync.