I hope this isn't off topic.
I found an old trick in an old box of mine.
My guess is that it is a mentalism effect.

It consists of a blue plastic board about 4"x6"
5 plastic clothespins - 2 pink, 3 yellow
4 black plastic pockets about 3"x5". Each one has two pieces of Styrofoam in it.
Two of the pockets have a piece of paper with a picture of a balloon dog

Any idea what this trick is? TIA