A jigsaw with at least some pieces being adapted to be placed alongside a plurality of other pieces by having an upper surface feature extending substantially completely along any one or more of the mating edges so that any other piece with a corresponding upper surface feature extending substantially completely along any one of the corresponding mating edges can be placed along side the or any one of the corresponding upper surface feature edges of the former piece. Preferably, the upper surface features extend completely along a whole number of mating edges and further surface features are provided along further mating edges of at least some of the pieces. Thereafter the surface feature remote from the mating edge may form a common border with one or more other surface feature remote borders. The invention allows the interchange of pieces to create new surface features.