Life changing magazines #2

Yes I know... I'm starting at #2, I need to track down the No.1 magazine. So this one was published when I was just 13, and it had the key equations for doing very basic 3D and perspective. I used these equations for years before real full matrices were possible, but it still holds a special place in my heart. And yes... theres a chunk missing from it. I got it 2nd hand, and someone had sent off for something ripping a big bit out of the article. Fortunately, it wasn't important as I didn't really care about the program, just the method and equations.