I have used these stop signs for years in my classroom and they are an absolute must-have. How they work is simple: Print them out in color and tape them together so that one side is side 1 and the other side is side 2. I am a firm believer in focusing on the positive and not drawing any attention to the negative. If a student is not following instructions or simply being disruptive, I place a stop sign on their desk on side 1. Usually, this is all they need. If it continues, I switch to side two and they realize they don't have any more chances. It's a great non-verbal. It's so effective that most students stop their behavior as soon as I start to walk over to the bin that holds the stop signs! Plus it's great that you don't have to speak to the student directly and you can focus on the positive in the room.