did someone say math jokes?
A Biologist, a Physicist and a Mathematician are sitting in a cafe. They see two people enter the condemned building across the street. A few minutes later, they see three people leave the building. The Biologist turns to his companions and explains, “They have reproduced.” The Physicist says, “The third must be an experimental error.” The Mathematician says, “If one more person enters that building, it will be empty again.”