> BUT THAT'S *NOT* THE POINT...

I understand.  I'm sorry I didn't make it clear that I do grok your
point, and I'm sorry that the change was not optimal.  Do you have
any suggestions as to how to make it clear for everyone (which was
my intent)?

Perhaps, "A collision occurs when two planes are within one unit of
each other in position and altitude." ?

-allen

-- 
                    Allen Briggs - briggs@ninthwonder.com