# Ellipse Rolling inside a Circle

Ellipse Rolling inside a Circle

This Demonstration draws the roulette of a generator point on an ellipse that rolls without slipping inside a circle.

Varying the ellipse's semimajor axis or eccentricity changes the circumference ratio between the circle and the ellipse. A closed curve can be obtained after complete revolutions inside the circle. By then, the ellipse will have made revolutions around its center.

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Change the pole offset to create an even greater variety of curves. The bookmarks and snapshots give some examples.