Shakashaka Sudoku Shakashaka - 200 Easy to Normal Puzzles 9x9 (Volume 23), Book 23, (Paperback)

Shakashaka (also known as "Proof of Quilt") is a logic puzzle.
The task is to place one of the four isosceles right triangles in some white cells.
Each triangle must occupy exactly half of its cell, but may be in one of four orientations.
Every contiguous white region must be a rectangle or a square.
A number in a black cell indicates how many triangles are adjacent to that cell by sides.