well-known type of puzzle in planar geometry requires to find a cut of a given complex planar shape that divides the shape into two identical parts (up to translation and rotation). Not all shapes can be so dissected, and for some shapes that can, the cutting curve may be quite surprising and difficult to find. In this paper we first analyse the inverse problem of assembling planar shapes from two identical parts having partially matching boundaries that allow self docking. Then we show how one can use the insights gained from shape docking analysis to derive an efficient algorithm to solve dissection puzzles of this type, by mapping the problems into string structure detection problems.