This optional lesson focuses on the idea of a tessellation: a repeating pattern that covers a plane with no gaps or overlaps. The lesson begins with a visual analysis of tessellations where students apply their knowledge of geometry and transformations to describe repeating patterns. In the next activity, students create and compare tessellations by making use of structure (MP7). Finally, students work to describe and recreate tessellations from a partner’s description. As they become more precise in their descriptions, their recreations become more exact (MP6). This lesson also includes examples of tessellations used in art from a variety of cultures, which can be explored as an extension.