i.e. one large circle with two smaller circled on top in the appropriate place, but Hidden Mickeys can take on many forms.
In designing, constructing or adding the final touches to an attraction, Imagineers subtly "hide" Mickey Mouse silhouettes in plain sight. Soon, it became a tradition, and as the word spread, Disney fans everywhere went on the search for Hidden Mickeys in Disney movies and theme parks.
So when you are at Disneyland - keep an eye out for them.
I will get you started: