Modern Discoveries

In the middle of dinner Laurence says, "Mom, did you know that a square is a rectangle, but a rectangle is not a square?"  I replied, "Yes, that's right...and yes, I did know that."  "Really?" he asked, clearly surprised.  "Well, sure," I told him.  "I went to school and learned all of that stuff, too."  "I know," he said, "but I figured shapes weren't discovered yet when you were a kid."