I encountered self-similar equations in regard to building factals. Or maybe I am confusing the idea of self-referrent equations. Anyway, if this helps, such an equation has a term which is first put in by hand. Then the solution to that equation is put back in the same formula term, generating yet another solution. That solution is again put back into the formula. In this way, the formula "evolves," that is, it either goes to zero or infinity, or, more interesting, it generates a pattern of results that may go on to infinite re-itterations. One such formula generates the famous Mandlebrot diagram.
Try searching for fractal theory, self-referent formulas, Mandlebrot diagram.
Hope this helps,
S