Many pots of food on the gas. Next to each pot is a clock. Next to pot number 1 there is a clock that shows that a quarter of an hour has passed, next to pot number 2 there is a clock that shows that half an hour has passed, next to pot number 3 there is a clock that shows that three quarters of an hour has passed, next to pot number 4 there is a clock that shows that an hour has passed