In geometry, a straight skeleton is a method of representing a polygon by a topological skeleton. It is similar in some ways to the medial axis but differs in that the skeleton is composed of straight line segments, while the medial axis of a polygon may involve parabolic curves. However, both are homotopy-equivalent to the underlying polygon. In geometry, a straight skeleton is a method of representing a polygon by a topological skeleton. It is similar in some ways to the medial axis but differs in that the skeleton is composed of straight line segments, while the medial axis of a polygon may involve parabolic curves. However, both are homotopy-equivalent to the underlying polygon. Straight skeletons were first defined for simple polygons by Aichholzer et al. (1995), and generalized to planar straight-line graphs (PSLG) by Aichholzer & Aurenhammer (1996).In their interpretation as projection of roof surfaces, they are already extensively discussed by G. A. Peschka (1877).