note gnosti I am pleased with the combined examples of overload, 'use parent' (as opposed to 'our @ISA =....') and a simple yet interesting application. <p> I think this is a great, minimalist way to understand OO, compared with a big black-boxish and black-magical Moose. <p> A functional example of solving the same problem, suggested by [lostjimmy], would be valuable for demonstrating a different approach. <p> Good work GF. btw, I'm impressed by your C.V. Hope any friends/family in Christchurch are okay. 889771 889771