The four sets of pearlescent playing pieces in Rumis each contain eleven of the twelve possible different polycubes; only the single cube is missing. In addition to the seven pieces of the Soma and Block By Blocks puzzles, there is also a square piece consisting of four cubes, straight pieces consisting of three cubes and of four cubes, and a L-shaped tricube.

The rules are blessedly easy to learn, without making the game play unchallenging. Choose one of the four playing boards, place it on the well-constructed turntable, then take turns placing pieces on the board. After the first move, at least one face of each piece must touch an earlier-played piece of the same color. The maximum height of the structure built over each square of the playing board is pre-set for each board. The winner of the game is the player whose color covers the greatest number of squares, when viewed from above.

There are also rules (or rather suggestions) for solitaire play, and the wise suggestion that two players should each play two colors. It's more challenging and fun that way. The game is supposed to mimic the elaborate stone buildings of the ancient Incas, so the four structures to be built reflect their architecture in shape. The pieces are well constructed, and the turntable is exceptionally steady, so that buildings do not fall as you turn it to get a better look. (We bought our Rumis game from Amazon.)