In Homer Price there is a story called "The Case of the Sensational Scent" wherein four robbers (count them, "four") stage a big heist on a live radio program and Homer eventually solves the crime and helps in the apprehension of the crooks.
A strange thing occurs to the reader's eye in one illustration that shows all of the robbers in one bed at a motel. Though it has been well established in text and pictures that there are four robbers there are suddenly five criminals in the bed at the motel! It's weird, it's actually kind of creepy! It makes me think of those movies where a mysterious person lurks in a scene who isn't supposed to be there, a ghost!
Here are some pictures, check them out, read the books, they are great fun for anyone.