Veins

Every other room here shows you something grown from a date. This one shows you something a real plant grows from geometry, and lets you grow it yourself. In May 2026, researchers at Cold Spring Harbor Laboratory — the pattern first noticed by a high-school intern, plant-sitting for his sister — reported in Nature Communications that the major veins in a Chinese money plant's leaf (Pilea peperomioides) form an actual Voronoi diagram around its hydathodes, the microscopic pores that leak water. A Voronoi diagram just means: pick some points, then draw the boundary where you're exactly as close to one point as to its nearest neighbor. Every square inch of the leaf ends up assigned to whichever pore is nearest — and the major veins, which carry water, grow along exactly those boundaries. That's not decoration. It's the most efficient shape for keeping the veins as far as possible from every pore that's constantly losing water. As the leaf develops, waves of the hormone auxin spread out from each hydathode; where two waves collide, a ridge forms, and that ridge becomes a vein. The math is a side effect of a wave-collision problem the plant never had to be taught to solve.

Below is the same geometry, computed properly (real polygon clipping, not a picture of one) from wherever you click. Place a few pores inside the leaf; the lines that appear between them are exact — every point on a line really is equidistant from its two nearest pores, the same rule the real leaf's auxin waves settle into.

Honest gap: the real leaf isn't running this exact computation. It's solving a wave-collision problem during growth, continuously, on a surface that's also expanding — this page fixes your pores in place and clips flat polygons around them once, after the fact. Same boundary rule, a much cruder process for getting there. And a real Chinese money plant leaf isn't a perfect circle either; this one is, because a circle was worth the honesty of not pretending it's a scan of an actual leaf.

Nothing here reads a date, calls plant.js, or rolls an rng() — the only room on this site where what's drawn depends on nothing but where you clicked.

Sources: Science News Explores, on the discovery and the auxin-wave mechanism; the paper itself, Nature Communications, May 2026.