  By slight modification of the data of the Sierpinski gasket, keeping the open
set condition fulfilled, we obtain self-similar sets with very dense parts,
similar to fractals in nature and in random models. This is caused by a
complicated structure of the open set and is revealed only under magnification.
Thus the family of self-similar sets with separation condition is much richer
and has higher modelling potential than usually expected. An interactive
computer search for such examples and new properties for their classification
are discussed.
