This is a 100% cotton sheet (13.5" x 27") printed with a modern-yet-timeless design of "Block."
The finished example shows it stitched using 3 colors of sashiko thread, but you can really design your own outcome.
The pattern does wash away.
Sometimes it's hard to know how to use a sampler once it's finished! You could use it as a dish towel, a mini (12" x 12") pillow case, carry it around as a fancy handkerchief!