'A mathematician who studied a very abstract topic was annoyed that
his peers in more applied fields always made fun of him.
'One day he saw a sign "talk today on the theory of gears", and said
to himself "I'll go to that! What could be more practical than a talk
on gears?".
'He arrives at the talk, eager to learn applicable knowledge. The
speaker goes up to the podium and addresses the crowd: "Welcome to
this talk on the theory of gear. Today I will be speaking about gears
with an irrational number of teeth".'