Wuensch MIT crystallography teaching (Eagar as student)

When I was a student, Professor Wuensch was my sophomore advisor, and he used to teach crystallography — the study of symmetry of crystals and whatnot. The students used to say, you'll never look at bathroom tile the same way again. He would give us some mosaic tiles from some Islamic mosque or some famous thing on the quiz, and we would have to figure out the symmetry features of that tile.