Ah, the AMF Magic Triangle. I remember the sight so very well as it was usually the first thing I would see when walking into Libertyville Lanes in Libertyville, Illinois. Of course that was back in the late 1960’s and early 1970’s.
Right now, I have an AMF Magic Triangle Masking Unit hanging in my basement. A friend salvaged it from a bowling alley that was closing down about 10 years ago. Someday my heirs are going to have a helluva estate sale.