The curious code 'A113,' which has featured in at least 45 animated films, TV shows and video games, is well known to people who work in the animation industry.
But for us, the viewers, the reasons behind the appearance of the secret combination has remained an unsolvable puzzle. Until now.
It can now be revealed that the 'A113' Easter egg is an "in-joke" between animators who all graduated from the same prestigious university, California Institute of the Arts. The code is, in fact, the name of the room in which animators at the university studied, including Disney's John Lasseter and Pixar's Brad Bird.
Bird said of A113: "I put it into every single one of my films, including my Simpsons episodes."
Even Bird's Twitter handle features the magic number: BradBirdA113.
Scroll down to see the movies in which A113 features!
In Finding Nemo, 'A-113' appears next to lens of diver's camera.
A Bug's Life
In A Bug's Life 'A113' can be spotted on a random cardboard box.
In Ratatouille, one of the rats' ears is tagged with the number.
Here in Brave 'ACXIII', A113 in roman numerals, is spotted just above a doorway.
Did you spot it? It's on the door!
Perhaps the most obvious of all the 'A113' easter eggs is the one shown above in our beloved Toy Story!