When we make worlds, there are maps, star charts, languages, fashion, technology, currencies, governments, peoples, and so much more. This post is about creating a magic system. More posts will follow on world-building.

Introduction

We're going to make a magic system of runes and spells that can be cast on the runes. This is but one approach of many. I made a prototype toy for this activity if you wish to play. I recommend spell books be made with ink on paper under a full moon.

Runes

A rune is a symbol, a glyph, an object that you give power.

To start, let's make a rune (or two). First, make a 4x4 grid:

And doodle some runes:

If you prefer a different grid, try hexagonal:

or polar:

Have fun, give them names, powers, and meanings.

These runes are just the start; you might add more to your collection, but let's dabble with some spells first.

Spells

Spells are what we can cast onto runes to change them. Let's use these runes:

with this spell,

...to make new runes for our magic system.

Now we have six runes:

There are other spells we can try, and if we like them, we can add them to our spell book:

Some spells might need two runes to work:

Some spells might do strange things:

Others might only work on some runes because they have conditions:

You might need to make runes to test your spells. Sometimes an experiment can help you find the capabilities of a spell, even if you don't keep the rune you used to test it.

If you'd like to play with a tool to make spells and runes, a prototype is here. Try to play and guess what spells do.

This is a good place to stop and think about what you want in runes and spells. Do you want polyhedra for runes? knots? braids? tangles? What spells can you cast with different objects? You can keep going with the approach above, or continue with your own.

A small note: Musical notes can be runes, and you can make spells for them (go up, make short, flatten, etc.)

Spell Books

Now that we know how to make runes, write spells, and cast them, let's make some spell books. Let's define a spell book as closed when the spells and runes within can only generate the runes within (no surprise runes).

This is also where a magic system can get deep and sometimes complicated. What does your set of runes and spells look like? Below are some ideas of how you might diagram how they interact.

Some examples from the diagrams:

The Pair ( involution, Z/2)

Two runes and one spell that toggles back and forth.

Orbit

The sink

Every rune becomes the same rune (the sink) when the spell is cast.

Even the sink stays itself:

The Cycle and Tail

All runes will eventually end up in a cycle.

Connections

Runes and spells connect to our lives, math, language, and so much more. Can you see if your spell book maps to the same structure as something else in your world?

A small note:
There are lots of directions to go with runes and spells. There are parallels with sets and operations, groups, category theory, and more. I purposely left spells and magic a little vague and open so that if you want to cast twists on braids, or stellations on dodecahedrons – awesome! The purpose of this activity is mostly to be creative. However, it can help develop what many of us do in a creative act of designing a language and its operations to then joyfully play and find out what it manifests. And sometimes we get to see how one invention or system is structurally the same as another.