Conway's Fractran traditionally compares the accumulator against reduced fractions, but computationally-speaking, getting to the gcd of a fraction does little more than getting rid of otherwise valuable information used during comparison to match against a restricted set of fractions. The support for catalysts, symbols found on both sides of a rewrite rule, makes for a simpler and faster implementation.
15/6 red [green] > blue [green]
5/2 red > blue
red green
I see, so you are using a different model for computation that does not use rational numbers, but instead pairs of integers. From a computational point of view, that makes a lot of sense, disallowing catalysts is quite annoying, but I would not call this Fractran, instead I would call it something like a prioritized chemical reaction network or something like this. The wikipedia article explicitly states:
> The same variable cannot be both decremented and incremented in a single instruction (otherwise the fraction representing that instruction would not be in its lowest terms). Therefore each FRACTRAN instruction consumes variables as it tests them.
I've seen this variance used a lot in the code golfing challenges I participate in, I feel like if I called it something other than Fractran, it wouldn't be long before someone points out that this is quite like fractran and I ough to call that