I have wanted to sew my own sheets for years. But the mitred corners scared me. Desperate for new sheets and broke with a huge stash of fabric in my basement I finally bit the bullet and did it. But I cheated. I cut a square of fabric to fit the top of my mattress. Then I cut 12 inch strips and sewed them all the way around the square. No mitred corners required! I love the results! Tomorrow I will zigzag elastic to the edge of my new sheets. I may never buy store-bought sheets ever again!