Shakashaka is played on a rectangular grid of white and black squares. Some black cells may contain a number.
The objective of the puzzle is to place triangles in some of the white cells. There are four kinds of triangles which can be put in squares:
In the resulting grid,
The white parts of the grid (uncovered by black triangles) must form a rectangle or a square.
Black cells with a number must be
orthogonally adjacent to the specified number of black triangles.[2]
Computational complexity
It is
NP-complete to decide whether a given Shakashaka puzzle has a solution.[3]
Furthermore, counting the number of solutions to a given Shakashaka puzzle is
#P-complete.[3]