[TR] Push or pull

[Randall]

> My adversary insisted 
> I was wrong and refused to discuss it further.  

Ask him if it matters which way a nut goes on a bolt.  Since the fan
effectively screws through the air, it's the same issue.

However, oddly enough, some fan makers do say to turn the blades around when
configuring as a pusher instead of a puller (in addition to reversing shaft
rotation by swapping the wires).  Apparently their fans are more efficient
when turning in a particular direction.

Randall