I saw a construction of an octagon inside a square and didn't believe how easy it was. The article was in Railroad Modeler, January 1976, pp.31. They drew diagonals across the square. Then the radius of half of the diagonal swung from the square's corners swing to the 8 points on the sides of the square. I checked the math and it was right. Carl.Blum (talk) 12:35, 11 April 2012 (UTC)