Emblem 21 of Atalanta Fugiens

A philosopher or geometrician stands in front of a wall upon which he is drawing a circle with a large pair of compasses. He is constructing this using some geometric rules from a circle with a square within a triangle. Within this central circle are a naked man and woman. On the ground in front of him are a protractor, a set square and a tablet with geometrical diagrams. He may be attempting to square the circle.