A man says he has come up with an algorithm for generating prime numbers -- all odd numbers are prime. Three ``experts'' are called in to verify this. All verify for different reasons:

**mathematician**- 1, 3, 5, and 7 are prime, the rest by induction.
**physicist**- 1, 3, 5, 7, 9 - experimental error, 11.
**engineer**- All odd numbers are prime.