I have a friend whom I haven't seen for years who was into street and traffic control signs. He took pictures of them and planned to do a picture book. Don't tnink he ever did, though. One that he spotted had been modified by scratching letters off. Originally it read

DANGER ZONE
IMPOUND
PARKED CARS

The edited version read

ANGER ZONE
I POUND
PARKED CARS

He planned on ending the book with the following sequence

ONE WAY
NO LEFT TURN
NO RIGHT TURN
NO U TURN
DEAD END

Don Firth