Angel Graphics was THE hot color separator in LA in the 70's and 80's. They wanted a giveaway poster to show what they could do, and I said I would do the art free if they would showcase me so I could get work from their clients, and also have a nice poster I could hand out.
Angel had several Heidelberg presses, so they knocked this out when there was some down time....it was a major job to strip up, though, and I remember them going nuts over it.
These examples of their logo were some of the first airbrush photocompositions I ever attempted. I think this was done in '82 or '83. It was this poster that got me the Magna job (!!)