The following are diagrams of the controls inside the three adjacent elevators in a real, existing building (where I currently work). Can you determine the usability problem that the elevator panels have?
Three images are provided. For the best time figuring it out, try to avoid viewing the images together, since if you were really in the elevator, you would only see one at a time.
For a bonus million points, see if you know which building this is. Hint: you won't.