Jacob's ladder puzzle. This puzzle, named after Jacob in the bible who saw a ladder or staircase descending from heaven, is a great optical illusion. Your friends, employees, family or clients will be amazed with the moving blocks. Watch as the blocks appear to slide down and yet there is always one block at the top that is always ready to descend. Products are not intended for use by children or pets. They may present a choking hazard to children under 3 years of age.