Tessellations are when shapes fit together to create pattern with no gaps and no overlaps. Here's a video of how I like to combined math and art in my tessellation lessons for students.
M.C. Escher was born the same year as my grandmother, 1998. He worked as an illustrator and artist. His ability to create elaborate repeated patterns served him well when designing tapestries but he also used tessellations in his etchings, lithographs, and woodcuts. Here are some of his more simple tessellations.
Because I teach a wide range of grades and ability levels, student work also ranges from simple to complex.