The Cubic Rube contains 5 of the 12 possible pentomino shapes, each made of 5 cubes joined. Kadon has been making the full 12-piece set, by name of Quintillions, since 1979. This subset, consisting of the F, P, T, U and W, plus one domino, was selected by Jerry Farrell, a renowned American puzzle designer, for an extra difficult 3x3x3 challenge for the puzzle collectors at the International Puzzle Party (2020). Kate Jones modified the challenge and extended the puzzles to many other goals.
The 5 pentominoes can fill 25 spaces in a 3x3x3 cube, hence the domino to fill the full cube. Not all figures shown need the domino. You can leave holes as needed.
Join all 6 pieces to form a cube without holes. There’s more than one solution. The domino will be at a corner.
Fit the 5 pentominoes within a 3x3x3 cube, with 2 single spaces as necessary. How many different positions of the 20 relative positions can you solve for the spaces? A couple of samples are shown.
We regret that this limited edition is now sold out. If you own a Quintillions set, or order Quintillions, you'll have all the pieces you need (except the domino) to experiment with building the Rube.