How to animate a piston in Bongo 1.0?

Here are some examples: http://news2.mcneel.com/scripts/dnewsweb.exe?cmd=article&group=bongo&item=2066&utag= http://news2.mcneel.com/scripts/dnewsweb.exe?cmd=article&group=bongo&item=1209&utag=

Bongo FAQ