At around the 12:00 minute mark is the moment that Fischer is given the puzzle which I am surprised Carson hadn’t seen before. I doubt the puzzle even exists today. Too mechanical for our day and age, too actually physically there and not electronic and online. Just have to slot the little squares till they are across from one at the top left to fifteen at the bottom second from the right. There is always a blank spot so that you can move a piece into an empty space. The example below is the puzzle solved but when you get it to work out it is always completely scrambled. Amazing to see Fischer was also the world champion at doing the 15 puzzle.