Good Die and Bad Die

Years ago...actually decades ago, I had a friend who ran a very simple game system that he called "Good Die, Bad Die". It basically worked on the idea that you added your good die (a d6) to your ability score, and a bad die (also a d6) to the difficulty score. So you wanted your good die to roll high, and your bad die to roll low. If you rolled doubles you'd generally succeed (regardless of the other numbers involved), but there would be an unexpected story twist. Ability scores ranged from 1 to 5, difficulties ranged from 1 to 5 (but sometimes you'd need multiple successful attempts to complete complex tasks, and ashe refined the system sometimes if your total end result was more than 4 points above the total difficulty result you might have earnt multiple successes on a single action attempt).

Characters were defined by three or four things that they were really good at (ability scores of 4+), a few things they weren't bad at (ability scores of 2-3), and a scattering of things that they'd dabbled in (ability score of 1).

I don't remember much more about his system, except that it was fast to play, loose with narrative and  was one of the first "minimalist" games I ever played. That was all back in the 90s (my hey-day of gaming), and I've since seen similar systems designed, published, popularised, evolve in different directions, become over-complicated from that raw simple kernel, then appear again in a new form through the writings of someone else. If the new person has a high-enough profile in the game design community, they are lauded for their innovation, even though the system has basically been reincarnated many times over the decades since I first saw it.

The reason I write this is that I've just realised the new game system I'm working on could probably be considered a variation on that idea of "good die and bad die". But instead of adding d6 to a flat number on either side of the action attempt, I'm offering variant die sizes.