[talkingtab]

A very long time ago there was a program on the Mac. You drew one picture (macdraw maybe), just lines, then a second picture. You could then watch as pix 1 morphed into pix 2. Anyone know where something like that is. A flip book for that would be great.

[latexr]

That is an animation technique called “tweening”. Using that term you should be able to find some software to do it.

[echoangle]

I would start with OpenToonz: https://opentoonz.github.io/e/index.html

It’s used by Studio Ghibli for making Anime and I know for sure that it supports tweening. And it’s free and open source.