Roriczer’s shield

“So einer ein schilt mit der geometry machen wil”: the workshop booklet Geometria deutsch, attributed to Mathes Roriczer, builds a shield from a square under the chief, a diagonal swung down the axis, and one arc for the base about a point between. Read as printed, that arc has the half width as its opening and misses the lower corners by 2.1 percent, ringed in red; the woodcut closes the shield anyway. Gold is shown by dots.