Today I wrote up a formal-ish, reader-facing explainer for one of the magic systems in my fantasy setting, The Patchwork Places.
To sum it up, it's basically sorcery as done through magical contracts, which at higher levels of mastery you can strike with anything, even the air around you, or more abstract concepts if you're really talented.
It's not necessarily creating anything new, as I've had all these magics written down in my notes for some time, but it is my first time presenting them to a wider audience, and the process of cleaning/polishing always does good things for the narrative clutter that otherwise builds up. Plus, it's a little more mental energy-friendly, which is nice to have right now.