based on the UV markings (security codes) and the lack of such a marking. They are: Nile, Pyramid, Circus, Egypt, Luxor, Tut and blank (i.e., the absence of any of the six security codes).

Each of those purposely manufactured variations also came in both a linen and a smooth finish, thereby creating 14 different variations.

By design, both sides of any chip was to have the same security code (or lack there of). However, due to production errors some chips were tagged with different front/back security codes (or the lack there of on one side), which produced various combinations.

If you look to the archives you will find where some contributors have listed the mis-matched combinations they have seen (or are in possession of), but I have not seen evidence of the existence of every possible combination.

So, there is only one graphic design of the Luxor $1 chip, but it comes in two different surface finishes (linen and smooth). Both the linen and smooth versions come in seven different UV (or lack there of) versions, resulting in 14 easily discernable variations.

Now, if you really want complicated, take a look at Greg Susong's FAQ page ( http://www.chipguide.com/cgi-bin/search/search.cgi?id=faq ) which discusses 4 different surface finishes for Chipco chips. 2 linen and 2 smooth. I have not seen posts that make a distinction between these four surface finishes and the 7 possible UV (or lack there of) markings.

Jim Follis