This is Piter Pasma's explanation about Signed Distance Functions.

Helpful links:
Code in this video: https://editor.p5js.org/triplezero/sketches/IeE6fvLY7
Earlier version of the same: https://editor.p5js.org/triplezero/sketches/rJ_46grmz
Circle packing with SDFs: https://editor.p5js.org/triplezero/sketches/iInAUsZF8
Inigo Quilez's articles: https://iquilezles.org/articles/
GENUARY: https://genuary.art

Thanks to @DenisovichPy for valuable feedback.

(From Youtube)