To make your own tessellations at home (or wherever you might have the supplies), begin with a small square. We used a three-inch by three-inch square (which happens to have an area of nine square inches). The square, of course, has four sides which we called the left, the right, the top, and the bottom.
With scissors, cut a non-straight line from the bottom to the top without cutting any pieces off. You will be left with two pieces that fit together like a puzzle.