Thus, in the Leftover Block Puzzle or almost any other, spheres might be substituted for rhombic dodecahedra. One advantage of spheres is that they are readily available in toy stores and educational supply shops, and usually quite accurate. The disadvantage is that they are more difficult to join together strongly. They can be bonded with epoxy, but an even better way with wooden balls is to drill holes and use dowelled joints. The substitution of spheres for rhombic dodecahedra is not exactly equivalent mathematically.
Spheres have an additional symmetry that the rhombic dodecahedra lack.
170, both of which have the same spherical counterpart. Thus, pieces made with spheres will generally produce more solutions and construct more figures, which could be an advantage or disadvantage depending upon the circumstances. Spherical versions also tend to fall apart more easily, so the pyramidal constructions may require a retaining base. Of course, spheres might also be substituted anywhere that cubes are used.