Now that you know how two ellipses can rotate such that they are tangent to each other and a third larger ellipse (

see this app); the next challenge is to figure out how an arc placed on each ellipse can be constrained (with proportional points along the ellipses) such that each arc always covers half of the ellipse and one endpoint is on the tangent point of the two smaller ellipses.

**Tags: Ellipses, conics, puzzler, arcs**