Spellchitects is a cooperative rpg or minigame where you design spells by drawing them. Specifically, you design spells by creating your own language of symbols and interlinking them until you've got a custom piece of magic.
So, you might decide the color blue is "cooling" and a single wavy line is "bolt." Draw a blue wavy line, and that's a blast of cold air.
But let's say you want to go further. You decide that the color black is "modifying", and that a circle is "explodes." You draw a black circle around a blue wavy line, and you've got a cryoball that immediately explodes when you try to cast it.
Maybe it gets closer to the intended function if you define square as "time delay" and draw a black square around the black circle?
Basically, this is the fun of Spellchitects. It's also got a gameplay mode where you try to fill orders for clients using the magic grammar you've constructed, but you can just as easily graft it onto your fantasy rpg of choice or use it as the core of a Rithmatist-style setting.
And if you do decide to bolt Spellchitects onto another system, it's also got an internal balancing mechanism where the more complex your spell is, the more components and syllables it needs. Some care may need to be taken to impose a high component cost on particularly powerful symbols or colors ("teleport" and "other" may not need to cost much, but "to the moon" probably should,) however this can easily be solved with a little bit of GM oversight.
Furthermore, you might be able to use Spellchitects to teach someone some of the ideas that go into coding---with the caveat that it's not really teaching a particular language, just the idea of using a language to reliably trigger specific results---and this alone should make it worth looking into for folks looking to run or write all-ages games.
The PDF for Spellchitects is 4 pages, with easily readable layout and a lot of fun color in the text, and I would heartily recommend picking up a copy.
-Page 4, 5th para, left side. "dictat" instead of "dictate"