Folding fitted sheets has never been a task that I have mastered. I watched my mother magically turn that bumpy, lumpy thing into a flat rectangle that fit perfectly in the linen closet. She is so good at it that to tell the flat sheets from the fitted I have to unfold them. Much to her irritation I'm sure, once I have done that, it's obvious!
I gave up trying to do them like her long ago, and much like a sweet lady I know confessed, I roll them into balls and throw them in the sheet drawer. (No nice orderly linen closets here).
Here is an excerpt of the book:
If you can figure it out from all that you are awesome!! I needed not only the diagram, but to have the sheet in my hand, and to read through the instructions 2 more times.