Great write up. If anyone wants to explore SDFs more, check out Inigo Quilez - he's a master of this stuff and a great explainer.

Painting a Character with Maths: https://www.youtube.com/watch?v=8--5LwHRhjk

And plenty more on his website in article form: https://iquilezles.org/articles/

Finally, Shadertoy, a graphics shader playground where you can see (and try!) a lot of this kind of stuff: https://www.shadertoy.com/