See Flight Experimenter.

So 'A' and 'B' are kept in memory? I don't really like that aspect Flight Experimenter looks janky for that reason), but the mechanic itself is quite interesting. I think the question is what kind of environment would want it? What are its mechanical and flavor implications for the world in question?

I imagine there would be some sort of A/B token, like energy counters, that you use to track it

Yeah, you'd have a dice or token to keep track of A and a dice or token to keep track of B, ideally placed in the center between two players so you know it's shared.

As for flavor implications, I'm honestly not sure. You can put it in a combo-focused or school/artifact-themed set. Or you can reflavor A and B to something like Light and Dark, which brings up a similar mechanic I figured might work - a sliding scale representing how dark/light-inclined the battlefield is, similar to how Dark/Light world tendency works in Demon's Souls. Something like

(-3)--(-2)--(-1)--(0)--(+1)--(+2)--(+3)

Where you have a counter that moves across this scale, with different cards caring about where on the scale the current state of the game is.

Honestly, this is a borderline silver border mechanic, and it's just something I thought would be fun and add another dimension to the game.

I like this. I don't think I would have used 'Algebraic' as its name (or 'A and B') since that's going to scare some people away by making them think there's higher mathematics going on, when there isn't. But that might be an appeal to some other group of players, so I'll duck out of the argument.

This does showcase one of the problems with Algebraic, though. Unless it has to do with creature power/toughness, negative values don't really do much in Magic. Draw -1 card, and discard -2 cards is meaningless... though, I could imagine your opponent intentionally re-casting Algebraic cards and decreasing the value below 0 in an attempt to make your Algebraic cards do nothing.

Maybe A and B shouldn't be allowed to go below 1? I don't know. I suppose it depends on whether you can prove the negative numbers matter on most, if not all the cards.

I already accounted for negative numbers in the reminder text - see "A and B start at 1 and cannot be negative."

I agree on the names, though. I renamed it to be called Numerology in the files, and I'd probably flavor this somehow if I were to use it in an actual set.

Oh, sorry about that. The comment about a counter that slid from -3 to +3 threw me. Very good, carry on.

Are A and B supposed to be global variables or specific to a player?

A and B are global variables.