Old_Zircon Same way as lenticular animation (which is basically the same thing except it's using refraction instead of masking stuff with vertical bars). The frames are cut into vertical strips and arranged so that as the mask moves across the paper, you can only see the strips that make up one frame at any one time. More or less.
Short answer is there's software that does it.
Hooker Does this qualfiy as an optical illusion? I thought optical illusions had to be distorting what is actually happening in your mind.
erratic the images on the paper aren't actually moving.
Hooker Yeah, I guess. This just seems like rather obvious animation. Does a flip-book count as an optical illusion?
erratic yes. animation is. I suppose all optics are illusion...if you think about. *bong hit*
The God of Biscuits I'll also chime in and be pedantic. This isn't an optical illusion.