Stop Sign Means Stop

Him: What does the stop sign mean on the test?

Me: It means you are to stop working on the test.

Him: Are you sure?

Me: Yes I'm sure.

Him: Ok.... *continues to work after the stop sign*

(later)

Me: Why did you keep working past the stop sign?

Him: I didn't know what the stop sign meant.

ME: IT MEANS STOP.