ParticleScroll is a full-screen scroll storytelling component that ties a Three.js particle scene directly to native browser scroll position. The visible canvas stays fixed in the viewport while an invisible scroll track drives everything: particle morphing between precomputed Float32Array frames, content panel transitions, and a progress strip that fills as the story advances. There is no scroll animation library involved. Progress is a single normalized float read from the element's bounding rect, scrubbed into the WebGL scene every animation frame. This piece walks through how the architecture works, what makes the developer experience feel clean, and where the shape system opens up for experimentation.