Happy faces

My parents still have a basket of baby toys from the early eighties, and I came across this one recently.  These happy faces are linked in such a way that they can rotate together and don’t come apart.  Here’s a question to ponder: Beginning with the orientation in the photo, if you hold one of the gears still and rotate the other one halfway around it, will the smiley be upside-down, right side up, or neither?