I was scanning some travel slides, and I accidently put two slides in the same scanner slot. Would you call that a double exposure? In any case, I totally love it! I rescanned the slides individually, in case you'd like to see which two pictures produced the above image.
These slides were taken in Maine, probably in 1983.
I tried it again with a couple other slides, but, of course, only came out with a dark blob.
Here's one more shot from that day. That's Ed stretched out on the rocks in the foreground.