TAOCP 7.2.2.1 Exercise 387

Section 7.2.2.1: Dancing Links

Exercise 387. ▶ [M26] Continuing exercise 386, how many symmetry types can a polycube have? Give an example of each type, using the minimum numbers of cubes. (Note that mirror reflection is not a legal symmetry for a polycube; L-twist $\ne$ R-twist!)

Exercises

The following exercises are based on several intriguing logic puzzles that have recently become popular: futoshiki, kenken, masyu, slitherlink, kakuro, etc. Like sudoku, these puzzles typically involve a hidden pattern, for which only partial information has been revealed. The point of each exercise is usually to set up an appropriate exact cover problem, and to use it either to solve such a puzzle or to create new ones.

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