I love that stuff.......what is it/are they?
A geometric pattern that is repeated (iterated) at ever smaller (or larger) scales to produce (self similar) irregular shapes and surfaces that cannot be represented by classical (Euclidian) geometry. Fractals are used especially in computer modeling of irregular patterns and structures found in nature
"...fractals are a unique art form using mathematical formulas to create art with an infinite diversity of form, detail, color and light. In simple terms, a fractal is a graphical image that represents the behavior of a mathematical equation."