Shiftable block puzzle

Claim 1

In a sliding block puzzle comprising a playing surface including formed channels therein surrounded by a rectangular frame, a plurality of rectangular playing pieces slidably positioned on the playing surface, said playing pieces including depending projections that fit into said channels, the projections further including extending portions below the playing surface that compatibly prevent the pieces from being vertically removed from the playing surface while allowing for slidable movement of the playing pieces through said channels in the playing surface, the size of the playing pieces being such that the pieces are positioned contiguously and fill the frame, with the exception that there is at least one vacant space inside the frame such that the playing pieces are slidable in perpendicular directions inside the frame and into the vacant spaces to change relative positions of the pieces on the playing surface, the improvement wherein an object piece is also slidably positioned on the playing surface, said object piece not having a depending projection and therefore being free to be removed from the playing surface, and further where the frame includes at least one opening therein at a predetermined location, the object piece being slidable through the opening allowing the exit of the object piece from the playing surface when the object piece is slidably manipulated to a position on the playing surface adjacent the opening.