This was a preliminary sketch for the tiling with matching alterations, but some people prefer the unaltered tiles that allow more incorrect placements... plus there is a beauty to the simplicity, I think.[br][br]The subsequent sketch is at [url=http://www.geogebratube.org/material/show/id/35252]http://www.geogebratube.org/material/show/id/35252[/url], and it has several links for learning more about Penrose tiles.

More GeoGebra at [url]mathhombre.blogspot.com[/url]