A biologist, a physicist, and an engineer are on a plane that crashes... ...and luckily they are washed up on a deserted island, along with several crates of canned food. However, no can opener washes up with them, and there is nothing sharp on the island, so the three scientists must figure out how to open the cans. The biologist sticks the can in the water, saying, ""The salt water should eat through the metal, allowing us to get to the food inside."" When this doesn't work, the physicist takes his thick glasses and holds them between the sun and the can, saying, ""By focusing the sun on the can, we can burn through the metal and get to the food inside."" But this doesn't work either. The engineer picks up a can and stares at it for several minutes before saying, ""Now, if we start by assuming the can is already open...""