Tesselations (Tilings) Tessellation is defined by a covering of a infinite geometric plane figures of one type or a few types. Quick History Sumerian civilization (about 4000 B.C.) The word was founded in 1660. The Latin root tessellare means to pave. -Stone paved streets in the 1600’s. 17 Wallpaper Tilings (Periodic)-1952 Penrose Tilings (Aperiodic)-Roger Penrose 1974 Tesselations A tiling is just a way of covering a flat surface with smaller shapes or tiles that fit together nicely, without gaps or overlaps. Tilings come in many varieties, both man-made ones, and ones in nature. Nature Science Decoration K-16 Curriculum K-5 Shape recognition Creating new shapes Tilings Polyominoes K-4th grade Video K-16 Curriculum 6th – 8th grade Isometries of the Euclidean plane Transformation Rotation Reflections Glide Reflections Symmetry Period vs Aperiodic Periodic vs. Repeating Tilings Up and Down Left to Right Test for Period Tilings Construct a lattice By the way it is made, you can see that a lattice repeats regularly in two directions. A tiling is periodic when we can lay a lattice over the tiling in such a way so that each parallelograms contains identical pieces of the tiling. Where would we see a periodic tiling? Fundamental Domain The pieces that are repeated in a periodic tiling is called fundamental domains. Can there be more than one fundamental domains? Four Kinds of Symmetry Slides Rotations Reflections Glide Reflections These different ways of moving things in the plane are called isometries. What types of shapes can be rotated? Four Kinds of Symmetry Reflections Four Kinds of Symmetry Rotations Four Kinds of Symmetry Glide Reflections Four Kinds of Symmetry Slides 5th-8th Grade Video Transformation Transformation Transformation Transformation Transformation Transformation Rotation Rotation Rotation Rotation Rotation Rotation Rotation Rotation K-16 Curriculum 9-12 Periodic vs Aperiodic Tilings Formal Description of Wallpaper Tilings Penrose Tilings Science Connections 12-16 Above with more detail Wallpaper Tilings Some of the most fascinating tilings are the so-called wallpaper tilings. These tilings are so symmetric that they can be built up by starting with a single tile by following simple sets of rules. But perhaps the most interesting thing about the wallpaper tilings is that there are exactly seventeen of them! 17 Wallpaper Tilings Symmetric Tilings 1:p1 10:p4 2:p2 11:p4m 3:pm 12:p4g 4:pg 13:p3 5:cm 6:pmm 14:p31m 7:pmg 15:p3m1 8:pgg 16:p6 9:cmm 17:p6m Kites and darts are formed from rhombuses with degree measures of 72° and 108° The kite and dart can be found in the pentagram The seven vertex neighborhoods of kites and darts The infinite sun pattern The infinite star pattern The two Penrose patterns with perfect symmetry The cartwheel pattern surrounding Batman Alterations to the shape of the tiles to force aperiodicity The kites and darts can be changed into other shapes as well, as Penrose showed by making an illustration of non-periodic tiling chickens Penrose rhombs Penrose rhombs The seven vertex neighborhoods of Penrose rhombs Decagons in a Penrose pattern A tiling of rhombs Print resources For all practical purposes: introduction to contemporary mathematics (3rd ed.). (1994). New York: W.H. Freeman and Co. Gardner, M. (1989) Penrose tiles to trapdoor York: W.H. Freeman and Co. ciphers. New Web Resources Wallpaper symmetries. Wall Paper Groups . http://www.kidsdomain.com/down/pc/tesselmaniap1.html Kali Tiling Software http://www.geom.umn.edu/%7Eteach95/kt95/KTL.html TesselMania Demo http://www.geom.umn.edu/software/tilings/TilingSoftware.html Kaleideo Tile: Reflecting on Symmetry. http://www.xahlee.org/ Computer Software for Tiling. http://aleph0.clarku.edu/%7Edjoyce/wallpaper/index.html http://www.geom.uiuc.edu/software/tilings/TilingSoftware.html Symmetry http://www.scienceu.com/geometry/articles/tiling/symmetry/p2.html More web resources http://goldennumber.net/quasicrystal.htm http://intendo.net/penrose/info.html http://quadibloc.com/math/penol.htm http://www.spsu.edu/math/tile/aperiodic/index.htm http://uwgb.edu/DutchS/symmetry/penrose.htm A Java applet to play with Penrose tiles: http://www.geocities.com/SiliconValley/Pines/1684/Penrose/ html Bob, a Penrose Tiling Generator and Explorer http://stephencollins.net/Web/Penrose/Default.aspx