1. Required cube The Solution must contain a ___ cube. The player selecting this variation specifies which non-digit symbol from the Resources fills the blank in the previous sentence.

2. Wild cube The ___ cube may represent any symbol on the cubes except a digit. The ___ cube must stand for the same symbol everywhere it occurs in the Solution. The player selecting this variation specifies which cube from the Resources is wild. The wild cube may not be a digit. Each Solution-writer must specify in writing the interpretation of the wild cube if it stands for anything other than itself in his Solution.

3. U and ñ interchangeable Any U may represent U or ñ, and any ñ may represent ñ or U. (Note: ñ means intersection.)

4. V and /\ interchangeable Any V may represent V or /\, and any /\ may represent /\ or V.

5. Two operations Each Solution must contain at least two operation symbols. The operation symbols are U, ñ, -, and '.

6. Multiple operations Every operation sign in Required or Permitted may be used many times in any Solution.

7. Shift from Permitted On your turn you may transfer a cube in Permitted to either Required or Forbidden. This move takes the place of your regular move.

Middle Variations

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