How did they do this “picture-in-picture”-like effect in old movies before digital video?

Question

There’s a scene in the original 1971 Willy Wonka movie which is sort of like a “picture-in-picture” effect. You can view it [here.](https://youtu.be/QkC8wPSmcPg?t=12) The main scene morphs into a square on top of a black background and there’s animated text that moves around and inverts and all this crazy stuff. I’m mainly interested how they sort of compressed the film frame onto a black background. I am wondering how they did this in 1970-71 on 35mm analog film before digital video and computers that could edit vide were a thing

In: Technology

Answer 1

I suspect they used the same technique from Mary Poppins in 1964. It’s live action with animation.