The extrovert looks at the other person's shoes.
Nothing.
One has a long smeller the other a loud yeller!
Her ankles.
Dirty looks from the mouse!
The extroverted mathematician looks at YOUR shoes when he's speaking to you.
An extrovert mathematician will be looking at the other guy's shoes.
They look at YOUR shoes when they talk to you.
He puts himself in the other person's shoes and then walks away.