The authors were inspired by Drawing Series IV, #413, to puzzle over what Sol LeWitt had in mind when he designed this wall drawing. The result is this paper, which describes a mathematical process involving group actions on a set by which LeWitt might have designed the piece. We also describe choice points in the process that are not mathematically determined and that produce interesting variations on a theme. The seed is one four-color square; the result is a beautiful and complex work of art.