Kudos if you get the joke A physicist, an engineer, and a mathematician each have their respective problem-solving skills tested by a group of researchers. They are each placed in separate locked 4x4 cells with walls made of cement and given a can of food. They are told to open the cans and get the food out using no other outside materials. The researchers leave the three to their own devices, then come back after an hour. The physicist is first to be checked on. The researchers find him mouthing out complicated formulas in his head. After a moment, he swings his can into a wall with the proper amount of force and at the correct angle to split the can open. The engineer is next. His cell is covered in dents, and he is eating from the remnants of a banged-up and broken can when the researchers find him. Finally, the researchers visit the mathematician's cell. They find him huddled in a corner, cradling the can in his arms, and muttering, ""Assume a can opener, assume a can opener, assume a can opener...""