This is very general challenge. It is to create a 3D fractal in CAD modelling software. It can be of any shape, any dimensions. Just interested in knowing what different ways we can come up with. They can get very complex, so may be we can limit ourselves to one of the following ones.
What is a fractal:
A fractal is a never-ending pattern. Fractals are infinitely complex patterns that are self-similar across different scales. They are created by repeating a simple process over and over in an ongoing feedback loop.
Hope this qualifies as some challenge. :D