Ballistospore Reach vs Radius: Buller's Drop Catapult (2D)

Mushroom gills fire their spores with a mechanism unlike anything else in biology: a hygroscopic droplet condenses at the base of each spore, and when it merges with the spore's surface the released surface-tension energy launches the spore sideways off its sterigma in about two microseconds. This 2D companion to the flagship 3D simulator numerically integrates that launch-and-drag trajectory frame by frame with an RK4 solver — rather than replaying a precomputed closed-form curve — and pairs it with a live reach-vs-radius chart derived from the same equations. The chart is the real payoff: it shows directly why gilled fungi only ever produce spores within a narrow size band, bounded below by spores too weak to escape the boundary layer clinging to the gill surface, and bounded above by spores whose momentum carries them straight into the opposite gill.