an example can be found on AMOSPro_Tutorial:Tutorials/Collision_Detection.AMOS
Detects COLlisions between one or more blitter objects. If a collision is detected, BOB COL will return a value of -1. Otherwise you'll get a 0 instead.
If you want to restrict your test to just a selection of bobs, you can optionally extend the BOB COL command like so:
c=Bob Col(source,first TO last)