Plants that are only rules. Each starts as one letter, and every generation rewrites every letter in parallel: F → FF, X → F[+X][-X]&X…. A turtle then walks the string in 3D: F draws, + − turn, & ^ pitch, \ / roll, [ ] save and return. Drag to turn the garden. The seed picks each plant's rule and angles; flowers at the tips are diatom rosettes.
LIT Lindenmayer systems (Lindenmayer 1968; Prusinkiewicz & Lindenmayer, The Algorithmic Beauty of Plants, 1990). ANALOGY diatom-rosette flowers. Self-check: the length of each rewritten string is predicted exactly from letter counts before it is built. ← SaPpH{{i}}on