Tautochrone Curve: a cycloid curve, when specifically oriented as shown, becomes a tautochrone path which has the special property that the time it takes for an object to slide to the bottom under gravity is the same no matter how high it starts up the curve. Also, the time it takes is always equal to pi times the square root of the cycloid radius divided by g. Presented here are three instances of two spheres being released at the same time, and each time they reach the bottom and collide at th