FISHY FISH (SHOJI)

This is a self-working and very deceptive puzzle where you show a picture of a fish that runs across three postcards. The cards are mixed so they are obviously out of order.

You turn the cards face down for a moment and when they are turned face up the fish is reassembled as it was before the mixing.

If you are not familiar with the principle involved, you will be fooled the first time you see it.