Five Parameters Elephant

"With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." von Neumann

c.f. http://java-srv1.mpi-cbg.de/publications/getDocument.html?id=ff8080812daff75c012dc1b7bc10000c

ported from http://www.physics.utoronto.ca/~phy326/python/vonNeumann_elephant.py