Q: Did you hear about the hungry clock?
A: It went back four seconds!

Explanation: To “go back for seconds” means to serve yourself more food from the kitchen, the serving dishes or perhaps the buffet line.  And you only “go back for seconds” if you are hungry.  The word ‘four’ (4) sounds the same as ‘for.’

A clock tells time by using hours, minutes and seconds.  In the joke, ‘seconds’ has two meanings: to go back in time four seconds and to go back for a second helping of food… and that’s what makes this joke funny.

Here is a classic scene from Oliver Twist by Charles Dickens when Oliver went back for seconds: