Actually, the special adhesive was invented in 1968, although an application for it was not found until 1974, when legendary pastor-DM Art Fry used it to make bookmarks for a hymnal. 1974! Coincidence? I think not!! And have you ever seen Gygax and Fry in the same place at the same time? No. You haven't. And that's because they are the same person. And let's not forget that pre-release versions of the commercial Post-It became available in 1977, just prior to the release of AD&D. Another coincidence? Right. Sure. You go on believing that, buddy. You go right on believing.