15-Minute City Isochrone Lab

Green-city planning increasingly centres on the "15-minute city" — the idea that every resident should be able to walk to a school, groceries, a park and a clinic within roughly fifteen minutes. This simulator turns that idea into a real, editable model: a street-grid city where you place the four essential amenity types and watch each block's colour update instantly based on its actual Manhattan walk-time to the nearest instance of each type. Tune the walking speed, the block size and the target time itself to see how urban form — not just amenity count — determines what fraction of a neighbourhood truly meets a 15-minute (or any N-minute) standard.