On Friday I posted this puzzle.

I have just made this video containing 10 bets that you will almost win (kinda). About 1 min in I present one of my favourite puzzles – the vanishing square.

You can download your own version of the puzzle here.

So, the puzzle is….why does a square seem to vanish?

If you have not tried to solve it, have a go now. For everyone else the answer is after the break.