Elliptical Gears The gears rotate and the point of contact lies between the foci.
Animate the gears by moving the point E Adjust the ellipses by moving B and C
Differentiation of first principle
Polygon Rotation as an example of Undo
Whistler Applet 2 Multiply with add ons
Q4 - Locus center of parallelogram
UnMessUpAble Shapes 1