Thanks to the following for code, examples or demos:

Duncan Murdoch, murdoch at stats dot uwo dot ca
Hans-Joerg Bibiko, bibiko at eva dot mpg dot de
Stefan Th. Gries, stgries at linguistics dot ucsb dot edu
Wacek Kusnierczyk, Waclaw.Marcin.Kusnierczyk at idi dot ntnu dot no
Taras Zakharko, zakharko at uni-leipzig.de