As I visited our student workroom one afternoon, a small group of students were killing time by kicking a miniature soccer ball around. As tried to walk by, one student tried to trap an errant pass and gave me a good kick in the shin. Of course, he was mortified.
Naturally, I had the only reasonable response to this stimulus: I quickly spotted a dark red index card and held it silently in the air in his direction.
Mean Green Math 