Introduction - If you have any usage issues, please Google them yourself
Board covered in a 2k × 2k a board consisting of squares, just a different box and other boxes, saying that the square is a special box, and said the board is a unique board. Coverage problems in the board, to use four kinds of different forms of L-type domino coverage given special board except in special than all the grid squares, and any of two L-type domino not overlap coverage.