Construct Ellipse with two Tacks, String, and Pencil

This video shows how to construct an ellipse using two tacks, a string, and pencil.


  1. Tie the ends of a string together to form a loop.
  2. Press a tack into the drawing paper
  3. Press another tack into the paper some distance away from the first tack. The distance between the tacks controls how skinny or wide the ellipse will be.
  4. Loop the string around the tacks and place the pencil within the loop.
  5. Rotate around the tacks, letting the length of the string form the shape of an ellipse.