A reproducible ridge-and-valley engine: rivers carve, snow caps, hikers march the ridge. Reroll the seed or paint rain with your pointer.
Every seed regrows the same range. Note a favorite number — the mountain waits for your return.
A diagonal channel carves wherever the cut slider runs deep. Canyon biome doubles its width.
Hikers march the mid-contour as dashed ants. Paint rain to raise lakes before they arrive.