Snap Cubes are used in K-12 math and art for all sorts of explorations and modeling. Try to put 1, 3, 5, 7 cubes into a nice-looking square. Model-making supports rich mathematical discussions and art work.

The cubes here measure 20mm x 20mm x 20mm by default, with three interlocking levels. To facilitate 3D printing, all the holes have a 45-degree cone inside. They all have 45-degree grooves inside to allow interlocking and free rotation. For teacher/student designers, this is an intermediate design project using Fusion 360.

Please use an infill greater than 20% for strength and try the fairly tight version, to begin with. Have fun!