This Instructional Activity is a part of the Lesson 2, Unit 9, Grade 8. The goal of this task is to introduce the notion of a tessellation and then carefully examine how to create a tessellation with each pattern block shape (square, rhombus, equilateral triangle, isosceles trapezoid). For hexagons, there is only one way to fit them together because there will be gaps unless three hexagons meet at each vertex. The other shapes offer much more flexibility, and students have an opportunity to use their artistic creativity. Students look for and make use of structure, both when they try to put copies of the shape together to build a tessellation and when they examine whether or not it is possible to construct a different tessellation.