[Broken] I have no doubt that this diagram has a specific name, and that it appears in Geometry texts. I don't now the name, or what text it may be in. It's plane Geometry, and it shows a definite relation of the radius of a Circle to the Line of it's Circumference. I may tie it into the thread on my discussion on calculating the volume of a sphere without using the standard equation or methodology of the classical geometers. Just for something to task on. As the circle [circ.] in the diagram is divided into six equal segments, I believe the illustration is, or may be illustrating, two pi radians; or at least can be described in those terms. I only intuitively understand two pi radians, though, so I may be confused. I have included a link to image, and will also include it as an attachment. I photographed the diagram with a camera phone, with LED flash enabled, and, and fan-dazzle. Well, the insert image tags seem to not be appearing, hope the attachment appears. I shaded some areas in the inner square for my own purpose.