On Tue, Jul 8, 2008 at 4:01 AM, Alan Gauld <alan.gauld at btinternet.com> wrote: > def __init__(self,p1,p2): > self.p1 = p1 > self.p2 = p2 > > And since a line should not have zero length (although > you might argue with that!) you could also check if > p1==p2 In this case he should define Point.__cmp__() so the comparison is by value rather than identity. Kent