9.1. Is it possible to place black and white pawns on the cells of a chessboard so that three pawns of the same color do not go in a row neither horizontally, vertically, nor diagonally? The chessboard is 8x8 in size. There is an unlimited number of pawns of both colors.
# Solution: 

Example of pawn placement:

| $\mathbf{4}$ | B | $\mathbf{Y}$ | b | $\mathbf{4}$ | $B$ | $\mathbf{4}$ | $b$ |
| :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
| $\mathbf{4}$ | B | 4 | D | $\mathbf{4}$ | $B$ | $\mathbf{4}$ | B |
| $\overline{5}$ | $\mathbf{4}$ | B | $\mathbf{4}$ | $\overline{5}$ | $\mathbf{4}$ | $\overline{5}$ | $\mathbf{4}$ |
| $\overline{5}$ | $\mathbf{4}$ |  | $\mathbf{4}$ | B | $\mathbf{\Psi}$ | $\overline{5}$ | $\mathbf{4}$ |
| $\mathbf{4}$ | $\bar{b}$ | $\mathbf{q}$ |  | $\mathbf{\Psi}$ | $\overline{5}$ | $\mathbf{4}$ | $\bar{b}$ |
| $\mathbf{4}$ | $\overline{5}$ | $\mathbf{4}$ | B | $\mathbf{4}$ | $\overline{5}$ | $\mathbf{4}$ | $\bar{b}$ |
| $\bar{b}$ | $\mathbf{4}$ | B | $\mathbf{4}$ | $\bar{b}$ | $\mathbf{\Psi}$ | $\bar{b}$ | $\mathbf{4}$ |
| $\bar{B}$ | $\mathbf{4}$ | B | $\mathbf{4}$ | $\overline{5}$ | $\mathbf{\Psi}$ | $\bar{b}$ | $\mathbf{4}$ |

Answer: Yes, it is possible.

| Criteria | points |
| :---: | :---: |
| 1. Correct answer, example provided | 7 |
| 2. Only correct answer. | 0 |