Jobsite Magic: Draw a Circle with a Framing Square?

Matt runs through the standard ways of drawing circles: compass, bigger compass, beam compass, trammel beam compass, stick, and stick with a notch—before he gets to a groovy little tape measure that makes it easy.

And then he draws a circle with a framing square.

Wait, what?

"This method is limited to the size of the smallest leg of the square, or 14 inches for a framing square." Notes Matt...

Drawing circles step by step:

• Drive nails at a distance equal to the circumference of the circle.
• Rest the short leg of the square against both nails.
• Put the pencil tip into the square's corner
• Rotate the square around the nails, keeping each leg against a nail until the second leg is in contact with both nails.
• Voilà: a semicircle.
• Repeat.