Chapter 6 reaches for physics libraries; the core trick is verlet integration, and a grid of verlet points with distance constraints is cloth. This expansion uses that cloth as a seismograph.
The page takes the same USGS feed as the earthquake walk and replays a week of global seismicity in a few seconds. Each quake’s longitude picks the column of the cloth it strikes, and its magnitude sets the size of the downward impulse, scaled by 10^magnitude. Strain coloring makes the largest events obvious: a magnitude 6 sends a visible shock through the whole sheet while the small ones barely register, which is exactly the point about how lopsided the magnitude scale is.
Data source: USGS Earthquake Hazards Program
Endpoint:https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_week.geojson
Access: Public, no key. Loaded from an hourly server-side refresh when possible, with a bundled snapshot fallback, and a live browser fetch only when the API allows CORS. Data window: Jul 11, 2026 - Jul 18, 2026 (pulled Jul 18, 2026 UTC)
Watching a week compress into seconds makes the clustering of aftershocks legible as bursts of ripples.