First, just another quickie to say that I have produced a new kindle ebook containing 101 Friday Puzzles! It is called PUZZLED (available in the UK here and USA here) and contains 101 puzzles and the solutions. If you are a teacher, trainer, have a curious disposition or just enjoy the blog, feel free to show your appreciation by buying PUZZLED!
This is really lovely – just get the gif running (you may need to click on it to open it in another page) and then stare at the cross. Bingo…..a black and white image appears in full colour. I have seen a few of these but this is by far the best.