A113 (Sometimes A-113 or A1-13) is an inside joke seen in animated films created by alumni of CalArts, referring to the classroom number used by animation students at the school. Brad Bird first used it for a license plate number in the Amazing Stories episode "Family Dog." It has since appeared in other Disney and Pixar movies.
Bird has said "I put it into every single one of my films, including my Simpsons episodes—it's sort of my version of Hirschfeld's Nina."
A113 is currently being used as the first year graphic design studio.