Please comment your solutions, questions and remarks..
I learned this puzzle from Juha Oikkonen, but it is probably quite famous anyway.
You have left your chess board on the table in the summer house and when you came back you found out that mice have eaten two opposite angle squares. The chess board looks something like this:
You have also a lot of dominoes with you. One piece exactly covers two adjacent squares of the chess board. Can you fill the chess board with the domino pieces such that they cover exactly all the chess board?
I believe that the answer is negative and the difficulty level of the problem is close to the number which separates negative integers from the positive ones.
:) that’s how it is, I guess. Although the level is not clear for me. If you do not think about the right thing in the beginning, it might take time to figure it out.