Euclid's Muse

Is this clock a circle, or a square, or something in-between, or something beyond? Not only do the hands move in this clock, but its shape changes with time. At the hour it is circular, at the quarter hours it is square and at the half hour, it has gone beyond square to a concave curved square shape. The morphing is achieved by taking a linear combination of the parametric representation of a squ…