Fractal
A shape whose small parts repeat the whole, again and again at every zoom.
See it in Fractal mirror. Pick Infinite zoom under Presets and let it sink into itself.
In plain words
Zoom into a fern leaf and each small leaflet looks like a whole fern. Shapes like that are fractals. Their detail keeps going as you look closer. Coastlines, clouds, trees and river maps all behave a little like this. A computer makes fractals by repeating one simple rule on smaller and smaller copies.