Pons Assinorum

See also:   [Literary Terms] 

The "pons assinorum" (Latin:  "bridge of asses) refers to a simple
THEOREM in Euclid's geometry (see map) which is SOOO easy to prove
that if you can't solve it (cross the bridge), then you might as
well give up and go shove your head into a pig. 

I think it's the one where you show that the vertical bisector
of an isocelles triangle also bisects the apex (top) angle of
said triangle. But, being a sort of Pons Medula Oblongata these
days, I wouldn't hazzard a guess at that sort of thing.