[Smalco]

This is flash based actionscript.

Go to this page : https://www.flashmxpro.com/, click fla and download Scale Mask Effect from Khan. That is exactly what you’re looking for.

[Smalco]

Thanks, that’s the one I was looking for.

Cheers,
Smalco

[Smalco]

I recall a site where they were drawn frame by frame.

https://www.proscreate.com/