The cover was done with screen overlays — thin, adhesive-backed plastic imprinted with screen patterns, in this case a graduated screen, which would be cut out and burnished down onto the illustration. Tricky to use. This scan from a third-generation copy of the cover is fairly rough, but it gives you the idea. Whatever you do, don't examine the structure I'm standing in too closely...

Here's a link to the cover for a cover illustration for another issue of Fangle that never happend.