Elipso - Ellipse Drawing Tool

The holder for pencil doesn't have any mechanism to tight it. In the end pencil can be easily moved inside the holder, which is not suitable for any kind of precision drawing. Alternatively I need to by thicker pencil, but still I find this as flaw of this tool rather than "not right pencil"

This device is useful, beautifully designed and demonstrates the parametric equations of the ellipse with great clarity. It is a treasure.

An ingenious mechanical device and a lot of fun to play with.