4952 · Confluence
Two watersheds meet — and their waters braid into one.
Droplets erode two seeded mountains in real time, rendered as a shaded-relief map. Both basins cut their own river tree and meet at a shared confluence, where a mixing interface keeps the two waters flowing side-by-side — cool thread and warm thread — before they finally blend downstream. The more unequal the two basins, the further the seam survives. Drag on the map to rain there.
Higher contrast makes the two mountains more unequal — the mixing seam survives further downstream, and the two voices take longer to resolve into one (Reseed rebuilds the terrain at the current contrast).
The map begins eroding the moment it loads — silent until you press Start (browser autoplay policy). Give it minutes: the channels deepen, the confluence sharpens, and the braided seam lengthens and slowly resolves. Minute five looks and sounds nothing like minute one.