Here are some pictures of a romanesco (a human derived, cultivated plant related to broccoli and coliflower) that I recently bought.
I find them interesting because of their fractal-like shapes, (self-similar at several size scales). In real life (as opposed to math-world), fractals have their limits due to the minimal size of their components (cells making patterns in a developmental field in this case). I read somewhere that romanescos can have 7 levels (or whatever its called) of fractal structure. This one has 5 that I could see.
The biology of how this happens has been worked out:
NY Times article
Science article
both paywalled.
Basically the meristem (growing part) keeps growing. A flower bud initiates a whorl. The flowering of each potential bud is blocked by mutations, but remain in the pre-flowering patterning state. Each bud in a whorl than can initiate a new whorl of buds, while can repeat the pattern until biological limitations of the plant stop the process.
Here a side view (partly dissected):
These are all from one plant stem.
The main stem (holding it all together) would be the first (largest or highest) level.
Each of the big branches in the picture would be the second level (also arranged in whorls), underlying the largest cones.
The smaller cones on these large cones are the third level.
Each of those cones have whorls (fourth level) .
A few of these have grown large enough to have their own whorls of little cones (fifth level).
This to me is one of those cases of the more you know about something, the more deeply you can appreciate it.