Non-linear Iterated Function Systems (IFSs) are very powerful mathematical objects related to fractal theory, that can be used in order to generate (or model) very irregular shapes. We investigate in this paper how Genetic Programming techniques can be efficiently exploited in order to generate randomly or interactively artistic "fractal" 2D shapes. Two applications are presented for different types of non-linear IFSs: # interactive generation of Mixed IFSs attractors using a classical GP scheme, # random generation of Polar IFSs attractors based on an "individual" approach of GP.