| Human lungs: the lungs exhibit marvelous fractal branching, twenty levels of branching hidden within our chests. | |
| Animal lungs: animal lungs also are fractal, but have geometries differing from that of human lungs. Note especially the manatee lung. | |
| Arteries: the circulatory system also is fractal, to get (a small amount of) blood throughout the body. | |
| Other examples: some nerve cells, the lining of the intestines, bone sutures, and others. | |
| Fractal fluid injectors: the architecture of the lungs can be inverted to build a remarkably effective chemical mixer. | |
| Heartbeat patterns: a chaotic heart is a healthy heart. | |