I like the snark mark. Although how many people would understand it? You can say stuff like "I don't like the snark mark: ~". ~ And then people start looking for pictures in the punctuation. So I'll never use the snark mark.
Teaching Symmetry Check out this symmetry self portrait bulletin board from Pineapple Paintbrush. Each child is half photograph and half drawing. I am sure the kids would love taking part in this project!