I never really liked coastlines as an explanation of fractals. Sure, they have some of the same features as you zoom in from the world map level to the calliper

I never really liked coastlines as an explanation of fractals. Sure, they have some of the same features as you zoom in from the world map level to the callipers-along-the-beach level. But it doesn't keep going forever -- you hit the atomic level where the coastline isn't so much fractal as poorly-defined.