The Square Does Indeed Describe the Circle!


The Romans used the square to layout the ubiquitous half-circle arc flutes along the length of their temple columns. You can too: Just set alignment pins at the start and stop points; hold the square against the pins; hold your marker at the apex of the square; and scribe away!

— Jim Tolpin,

This entry was posted in Uncategorized. Bookmark the permalink.

7 Responses to The Square Does Indeed Describe the Circle!

  1. That is one of the most interesting ideas I have heard for some time Jim. I wonder why they didn’t just use a length of string and a couple of nails?

    • jtolpin says:

      I think this method is probably faster than cutting string to the exact length and tying it off. All you have to do here is grab your square (or your libella sans the plumbline) and a pencil and go to it. Plus string can stretch unless properly laid and of the correct materials (which traditionally might be fibers taken from the female hemp plant–and not the male—or maybe I have that backwards–I don’t know where you look to find out anyway!

      • You can describe a circle with a single nail and a string. If you try it with two nails and a string, what you get is an ellipse with the two nails as Foci of the ellipse you made.

        (Unless one nail is used as the scribe)

        We all knew that back when we were building temples.

  2. rdwilkins says:

    Fantastico, è funziona!

  3. amvolk says:

    I often learn just as much from these comments as from these great articles. Thanks to you all!

  4. Mark Allen says:

    The 90 deg angle on the square gives the circle, but you can do ellipses if you have a template < 90 deg.

Comments are closed.