Is there any easy way to do vertical matching/replacements in Retina? (Run regexes on the transposed input?) I am trying to make stuff work with balancing groups, but I need to reuse the "length" of a group's stack, and I don't know how to do that. It'd be much easier if the input could be transposed.

@mbomb007 I don't know how much this can help you, but here's a way to transpose square inputs Try it online!