Introduction - If you have any usage issues, please Google them yourself
In a 2k x 2k (ie: 2 ^ kx 2 ^ k) consisting of checkerboard squares, and a box with the other box, saying that the box is a special box, and said the board is a Special board. In the chessboard coverage, the use of four kinds of icons of different forms of L-type domino to cover all the squares on the board except for special given special box, and any two L-shaped dominoes not overlap coverage