I am a big fan of riddles, especially those which are extremely simple to explain while having an elegant solution. So, here it is one of my favorites!

Imagine I give you a chessboard with its classical 8×8 squares, but without the top left and bottom right corners (see image below).

Question: can you fill the entire board with pieces of dominoes? Note: each domino occupies two adjacent squares, so diagonals are not allowed.

More than 15 years ago, when I was a naïve young teenager, I discovered this riddle in the book Fermat’s last theorem by Simon Singh (I highly recommend it!). This problem was an example of a mathematical proof without using brute force. The simplicity of the solution just blew my mind. Since then, I became an amateur riddle collector. I hope you also enjoy solving this little problem!