Dark Knight Returns Production Page

I've been seeing some of these production pages on ebay lately, and thought I'd pick one up. Not exactly sure of their origins, but they appear to be printers proofs of some kind, and may have been distributed with anniversary copies of the DKR TPB. They consist of two layers; one is the color art (computer printout), and the other is a clear overlay containing the black and white line art. I took some time and created another overlay that contains the lettering so you can actually read the page (click for larger image). Coincidentally, this page immediately follows the original page that I own from the book.