Self-similarity is a dull subject because you are used to very familiar shapes. But that is not the case. Now many shapes which are self-similar again, the same seen from close by and far away, and which are far from being straight or plane or solid.

A fractal is a mathematical set or concrete object that is irregular or fragmented at all scales...

I was in an industrial laboratory because academia found me unsuitable

One couldn't even measure roughness. So, by luck, and by reward for persistence, I did found the theory of roughness, which certainly I didn't expect and expecting to found one would have been pure madness.

The most important thing I have done is to combine something esoteric with a practical issue that affects many people.

I spent half my life, roughly speaking, doing the study of nature in many aspects and half of my life studying completely artificial shapes. And the two are extraordinarily close; in one way both are fractal.

Fractal geometry is not just a chapter of mathematics, but one that helps Everyman to see the same world differently.