A complex three dimensional organism self-assembling from a single cell is 100% magic, especially given how resilient it is to disruption. You can kill one of the two cells produced by the first division and still get a fully formed organism (that's one of the actual early experiments in morphogenesis theory).
Concentration gradients layered on concentration gradients layered on concentration gradients.
https://en.wikipedia.org/wiki/Segmentation_gene