Problem Is it possible to tile a $13 \times 13$ board with $4 \times 1$ dominoes such that the center square is left untiled?
I was not able to find a tiling so I am trying to prove that it is no possible.
I tried the usual way of coloring the board with $4$ colors using a chessboard style alternating coloring. Lets say the colors are $1, 2, 3, 4$ then I find that we have $43$ $1$’s, $42$ $2$‘s, $42$ $3$‘s, $42$ $4$’s and the center ($7^{\text{th}}$ row and $7^{\text{th}}$ column) cell has color $1$. But then this meets the demands of the $4 \times 1$ dominoes, so there is no contradiction.
Any hint will be helpful. Do I need to do a different kind fo coloring?