Q: If you meet an engineer at a party, how can you tell that he (and sometimes she) is an extrovert?
A: He's the one who tells the joke that starts, "If you meet an engineer at a party, how can you tell that he is an extrovert?"
A: He's the one who tells the joke that starts, "If you meet an engineer at a party, how can you tell that he is an extrovert?"