In a box with the easels in a lot of darkroom equipment I acquired. Plastic blocks fit inside frame and are held in place by plastic sheet that slides into tracks on edges of frame. Plastic blocks have + on one side and - on the other. Whoever can tell me what it is gets a solid pat on the back. Apologies for the crappy cell phone pic.
It's an easel for printing multiple images on a single sheet of paper. The negative and positive symbols allow you to keep track of which sections have been exposed.
Ok, now it appears obvious. The guy also had a Saunders Multi-Print in there. Anyone know the manufacturer? It's Saunders colors, but doesn't seem up to their build quality. In almost 30 years of hoarding photo junk, this is the first one I've seen.
You know, I got one of those in a huge bundle of other darkroom stuff. And since then, I could not for the life of me figure out what the hell it was or how it worked (and obviously too lazy to google it).
Now I finally understand...