J. Ryan Sobol wrote: > Are negative numbers and zero allowed to be a starting point or > target? I'm assuming no, but I'd like a confirmation. > > ~ ryan ~ I made a quick analysis: target - 0 + - ok ok ok 0 no ok ok + no no ok start but, to make it simpler: let the domain be positive integers. It all depends on the operators used. With the proposed operators, it is possible to go from any positive number to any positive number. Christer Nilsson -- Posted via http://www.ruby-forum.com/.