In message <42d2ba4b@news.povray.org>, B. Gimeno writes >#include "colors.inc" > >penrose's tilings are one of my obsessions, how do you made this mosaic? >manually? Hardly! There is in fact a fairly large area covered with tiles. They were generated by a recursive macro (actually 2 of them) which carries out a process known as inflation. Each stage involves scaling up the tiles by the golden ratio, and then replacing each tile by several other tiles the same size as before. There is one substitution rule for fat rhombs, and another for thin. So starting with one tile (or a manually placed small selection), each iteration of the inflation process creates a larger tiling than the one before, until you run out of memory. Unfortunately, every time I try searching the web about a particular aspect of Penrose tiles, I find out everything else except what I want to know. I worked out the inflation rules for rhombs by observing Fractint's (winfract) L-system (fractint.l - Penrose 1-3) Note that this does produce a lot of duplicate tiles, although they all overlay each other perfectly. See pic below for the substitution rules, the orientation of the tiles is important (hence the little circles). I can post some example code if you like, it'll probably need a few comments added to it first. >pretty image, by the way. Thanks.