When talking to you, the extrovert mathematician looks at *your* shoes.
Cleavage.
Nobody, he had no one to look up to.
He was a little horse
Because it's not polite to talk back to your paw !
I'll tell you guys later.
Europe"
During any conversation he's looking at YOUR shoes.
They are looking at your shoes, rather than their own.
So he could look at others' faces.
An extrovert mathematician will be looking at the other guy's shoes.