This is the Mister Square story.
See how happy Mister Square is today. Yesterday, he wasn't too pleased (turn card upside down) because it rained so much. But today he is glad to be going on his holidays. He soon arrived in sunny Niagara Falls, and decided to book into the motel right away. "Hello," said the man at the reception, "can I help you?" "Yes," said Mister Square smiling broadly, "I would like a room with a nice comfortable bed."
There were not many other people there at that time so Mister Square had the choice of rooms. The first one he went into had a large (square) bed. What shape is this? Mister Square tried it but his feet fell right out one side, and his arm the other. It wasn't very comfortable so he decided to have a look at some others.