Shakashaka (シャカシャカ) is a logic puzzle developed by publisher Nikoli.
[1] Shakashaka is played on a rectangular grid of white and black squares.
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, 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.