A three-dimensional platform comprising a tessellated surface of pieces, each piece comprising a top and sides. The pieces comprise a fixed square piece having at least two opposing sides orientated acutely relative to the top to define a fixed square retention surface. The remaining surfaces orientate substantially perpendicular relative to the top. There is a mobile square piece having at least two opposing sides orientated obtusely relative to the top to define a mobile square retention surface. The remaining surfaces are oriented substantially perpendicular relative to the top. A mobile triangular piece having all sides orientated obtusely relative to the top. The fixed square retention surface indexes only with either the mobile square retention surface or the triangular piece surface to effect retention of the pieces to define the three-dimensional platform.

The present disclosure provides a sliding puzzle. The sliding puzzle includes a cylindrical support and a plurality of blocks. The cylindrical support provided with two opposite bottom surfaces and a side surface connected between the two bottom surfaces, wherein the side surface is provided with a guide rail structure. Each of the blocks is mounted on the guide rail structure and can slide along the guide rail structure to change a position. The sliding puzzle in this solution can effectively decrease the possibility of loss of block parts in an assembling process of the sliding puzzle and improves the convenience of use of the sliding puzzle. Meanwhile, compared with the paper card type and plastic sliding puzzles, the sliding puzzle in this solution improves the stereo perception and the funniness. The sliding puzzle is simple in structure, convenient to assemble, and connected firmly.

An aid for teaching mathematical concepts looks like a multiplication table but has separable rows of numbers. In the first row, cardinal numbers 1-n are displayed and second-N rows have cardinal numbers 2-n displayed along side one edge on the face. The remainder of the rows have the multiplication products of the cardinal numbers on the first row and the cardinal numbers of the rest of the rows arranged at the intersections of the cardinal numbers at the top and along side the edge. The rows are separable so they may be arranged in a multiplicity of pairs of fractional equivalents.

The present disclosure provides a sliding puzzle. The sliding puzzle includes a cylindrical support and a plurality of blocks. The cylindrical support provided with two opposite bottom surfaces and a side surface connected between the two bottom surfaces, wherein the side surface is provided with a guide rail structure. Each of the blocks is mounted on the guide rail structure and can slide along the guide rail structure to change a position. The sliding puzzle in this solution can effectively decrease the possibility of loss of block parts in an assembling process of the sliding puzzle and improves the convenience of use of the sliding puzzle. Meanwhile, compared with the paper card type and plastic sliding puzzles, the sliding puzzle in this solution improves the stereo perception and the funniness. The sliding puzzle is simple in structure, convenient to assemble, and connected firmly.