I remember reading an article about one of the animators or layout artists on a Disney animated film sneaking in one of their own original abstract paintings into a frame.
I thought it was Bill Tytla, but Google is coming up empty. I also thought the film was Dumbo, but again, Google doesn't have any real hints. I am 99% sure it was a classic era film, so pre-Jungle Book and most likely pre-Cinderella.
Does anyone else remember reading something about this? Can you identify the artist and the film?