It is mainly formed by some parallelepiped base parts (1) with a perimetric groove in their edge for insertion of tongue pieces (3) emerging from some of the edges. They are provided with at least one axial recess receiving another part materialized by a stepped cylindrical button (5) that can rotate in its lodging upon having four peripheral axial pins (7)that are housed in a ring-shaped recess (6) of the base part (1), concentric to the respective recess. The ring-shaped recesses (6) as well as the axial pins (7) are found on both surfaces. The cylindrical button (5) has a diametric groove (9) open to the periphery.
There are other triangular parts (13, 14) upon diagonally cutting the square base parts (1), there also being interconnecting projections (15) and recesses (16).
It includes some hinge-type articulating parts (17) whose limbs are similar to the square base parts (1).
It also has covers (19) that fit together and in the axial recess (4) by means of a ring-shaped recess (6) of any of the other parts; there also being triangular covers (20) as half elements.
This allows the formation on the playing board of mosaic drawings with square (19) and triangular (20) covers.