A 4x4 grid is all you need to invent a magic system of runes and spells
Creating Worlds: Runes and Spells Prototype
A playful world-building exercise that turns simple grids into runes and treats spells as operations cast upon them: reflections, rotations, intersections, unions, and conditional effects. A free browser prototype lets you experiment, and spell books can be analyzed as closed systems with toggles, orbits, sinks, and cycles — quietly echoing set theory, group theory, and category theory without ever demanding the math.
A small note: Musical notes can be runes, and you can make spells for them (go up, make short, flatten, etc.)