Fastest slide

draw a slide. try to catch the gold marble.

draw a slide between two rings and race it against the straight line and a hidden gold path

A straight line is shortest between two points, but not fastest under gravity: dropping steeply first builds speed early. The fastest curve is a cycloid. No friction here; a real marble is slower on every slide, so the winning shape stays the same.

Concepts: gravity, energy, optimization, geometry.

An interactive you play with one thumb, on Wundr.