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The Lab · Bench
EXP-016generativeLive

Contours.

A topographic map with nothing underneath it. Press anywhere and a mountain rises under your finger, every contour ring redrawing itself around the summit in real time; switch to carve and dig until the sea floods back in. The sheet opens the way it works: the water drains off the land, and each ring appears the moment the sea drops past its level.

Marching squares · Live terrain

 

Press anywhere to raise a mountain.

Hold and the land keeps rising under your finger, contour by contour. Switch to carve and dig until the sea floods in. Drag to draw ridges and valleys.

Bench notes

The algorithm
Marching squares, the workhorse that turns weather models and CT scans into pictures. The terrain is a grid of heights; every frame, each little square of four values is checked against each elevation, and where a contour crosses its edges a line segment is interpolated. Around eleven thousand squares, every sixtieth of a second, from scratch.
The cartography
Borrowed from real topographic sheets: light minor contours every 30 meters, a heavier index line every fourth, dashed bathymetric lines under the water, and coral summit marks with live elevations once a peak clears the treeline. The compass, scale bar, and graticule crosses are furniture, but a map without them never feels like a map.
What to notice
Spacing is slope: where the rings crowd together the ground is steep, where they spread it's gentle. That's the entire trick of a contour map, and you can feel it here by making the terrain yourself. Then stop pressing: the land keeps settling, because the map slowly erodes everything you build.