Voronoi diagrams of Penrose tilings are extra cool. There are six at the bottom of this page: http://www.josleys.com/show_gallery.php?galid=284

I'd love to see it as real tiles. The nicest looking might be pearly-white granite or quartzite, with pink granite for the pentagons. Adding grey into the mix, I think a floor could be done without same-color adjacent tiles. I wonder where I could buy this.