Gestalt

The image I made was one of just 6 simple circles all in a line. The two Gestalt principles at work here are continuation and similarity. As you look at the circles your eyes naturally follow them in a row because it looks like they all go together and it's only normal that each would follow another. There is similarity here because your eyes also naturally lump together the four red circles apart from the two blue circles. It always seems like similar figures go together, even when they may not.

The picture I found out in the world that showed Gestalt principles was this picture of a motorcycle. As you can see, most of the pieces of the motorcycle aren't connected to the rest of the bike, like the front wheel. But with the principle of closure, we imagine that this is a round wheel that just connects behind that bar in front of it. We don't see it as a partial circle.