mouse to drag control points space to create a new control point at the mouse L to toggle closed loop mode left/right arrows to reduce/increase curve steps modes (press the corresponding number key): [1] cubic hermite [2] catmull-rom [3] kochanek-bartels
https://en.wikipedia.org/wiki/Cubic_Hermite_spline https://en.wikipedia.org/wiki/Kochanek%E2%80%93Bartels_spline
