Image via WikipediaDoes a three legged stool have reflectional symmetry in a plane rotational symmetry about a line or both? - Yahoo! Answers:
"Rotational symmetry means that you can turn it in a circle and you can't tell it moved. If the stool has three legs and a circular head, you can turn it a third of the way around and it would look the same. Reflectional symmetry in a plane means you can split it in half and both sides look the same."