Answer: A Classroom

We’ll admit that we’re suckers for a good Easter egg and when it comes to Easter eggs, this particular one is very persistent and fun to hunt for. Throughout Pixar’s films, you’ll find references to the simple alpha-numeric code “A113”. Sometimes it’s pretty obvious, like the license plate from Toy Story in the image seen here. Other times it’s pretty well hidden, like when it appears as graffiti in Inside Out or is even broken into two components representing the location of Mr. Incredible’s cell, Level A1, Cell 13, in The Incredibles.

What’s even more impressive about this persistent Easter egg is that it reaches well beyond just Pixar films—you’ll find references to it in The Simpsons, The Brave Little Toaster, Lilo & Stitch, The Iron Giant, and even in the live-action super hero film The Avengers. So what’s the deal with A113?

The reason you find it throughout Pixar films and in a variety of other films is all thanks to the graphic design and character animation program at the California Institute of the Arts. For years, first year students met in the A113 classroom and, after cutting their teeth at the influential design school, went on to work at esteemed studios like Pixar and Walt Disney. Including the A113 Easter egg is a subtle way to pay respect to where they came from as well as give a little shout out to all the other animators they shared the classroom with over the years.