In responding to the post of CherylL.
This, also, is a double exposure but a bit different. This is a double exposure on the negative.
I was on the stage and wanted a shot of the drummer but there was too much clutter in the way. I found myself in a spot where to my right were equipment stands and light tree stands, and to my left was a very large speaker. (about 5 foot by 5 foot by 6 or 7 foot high. I couldn't move any more to my right because the speaker blocked half of my lens. AH HA !! So I took the shot on half the frame, the went around to the other side of the speaker, allowed the speaker to block the first half of the frame, set my camera for a double exposure, and took a second shot on the other half of the frame.
Canon F1-N, 135 mm lens, Kodak 1000 asa, f2.8, 1/30.
View attachment 263090
It's not an image over an image, but one side by side.