If a rule is broken that card is turned over so you can't see the smile. This is a warning. Each time a rule is broken the card is moved to the back of the pocket. In my room green follows purple, then yellow, then red. Each card turn is assigned a consequence.
Consequences get progressively worse, with a red card being a referral to the office.
I was worried at first because I had always seen this used with younger students, but I have a difficult class this year and the cards are very visual and serve as a constant reminder of expected behaviors. I explained to my students that green was like a traffic light and if they were on green to roll along as they were doing, that yellow was like a caution light, a warning to slow down, be careful. The blue one was like the flashing blue light on a police car, you have been pulled over. Call home, Go to the Principal's office, Sit out at PE, or whatever. Debbie 4 .