The Five Squares Into Four puzzle is a "bar-bet" challenge to change a configuration of five squares into configuration of four squares by moving two sides. The two sides remain in play. Originally, the puzzle was done with matchsticks. There are no tricks to this puzzle. The five squares are laid out as 16 sides on a 5 x 7 grid of playing space. The player selects an occupied side to move and then selects an unoccupied side to move to. The side moves as ordered. Then a second side is selected and moved. If the new configuration has four squares, the player has successfully solved the puzzle.
There are three control buttons: Restart, Demo, and Info. Restart restores the view to the starting position of the Five Squares. Demo demonstrates how to solve the puzzle. Info contains the rules, a hint, background information and the support website url.
I became acquainted with the Five Squares Into Four puzzle in the early 1980s but I believe it is much older than that. It was a popular bar bet and usually done with matchsticks, preferably the old wooden ones. A rumor at the time was that the puzzle was presented to a graduating class at West Point Military Academy. The puzzle was given to several hundred cadets in an auditorium with viewgraph projector. All graduating cadets receive a bachelor of Science degree. At the end of 20 minutes about half of the class had solved the puzzle of Five Squares Into Four. At the end of an hour 15 cadets were still struggling. Apparently, there was no relationship between class standing and success at solving the puzzle. What I have found in my own experience is that a few women have solved the puzzle immediately. They solved it in 20 seconds or less. I do not remember a man solving it in less than five minutes.