Using the embroidery hoop, floss, and needle, begin stitching around the leaf shape. We used a split stitch: Start with one straight stitch, then bring your needle up through the underside of the fabric to split the strands of floss in the original stitch. Continue until you've stitched around the entire shape.
Using embroidery floss that is a shade lighter, place a second row of split stitches just inside the original to create a thicker outline. Follow the same instructions as in Step 2. Repeat for all leaf shapes on your pillow. When finished, sew the embellished square to the plain square to create a pillow cover.