a puzzle

[zwol]

Given two shell variables, A and B, each of which is a space-separated list of numbers, how would you iterate over the lists in parallel, comparing each pair? That is, compare number A₁ to number B₁, A₂ to B₂, and so on. You may not use features not available on old systems (such as functions, arrays, and local variables) and you may not mess with the positional parameters. Comprehensibility is not important.