Atarimania Forum

In an ad for Analog magazine's Compendium book, they listed a program called "Sketch Pad". Alas, it didn't appear in the book, and I'm not sure it even appeared in any issues. Anyone know more about this?

Here's a copy of the ad, which features a screenshot of it:

http://web.comporium.net/~scottith/ANAL ... ium-ad.jpg