Forbidden Crystal Symmetry: Mathematics and architecture - Roger Penrose
World-renowned mathematician Sir Roger Penrose, Oxford University, describes how crystalline symmetries are necessarily 2-fold, 3-fold, 4-fold, or 6-fold.
World-renowned mathematician Sir Roger Penrose, Oxford University, describes how crystalline symmetries are necessarily 2-fold, 3-fold, 4-fold, or 6-fold.