http://www.jawa-trader.co.uk

Nestle Asia/Mexico Episode 2 3d motion/morphing cards - (2002) set of 6

This shows the back with a diagram which explains the little window

Nestle 'Poland' Episode 2 3d motion/morphing cards - (2002) set of 6

These are a lot smaller than the Asia/Mexico cards, the backs are just blank.
I'm not sure now if the above cards are Polish ...

However I do think this one with the 'round corners' may well be !

These images show the varying sizes

They all morph between scenes

http://www.jawa-trader.co.uk