Hold the two pieces of fabric parallel to each other with right sides facing and cast-on edge at the bottom. Insert the tapestry needle from the back to the front between the first two stitches on the first piece of fabric just above the cast-on stitch. Pull the yarn through, leaving a 3-inch tail. Insert the tapestry needle from the front to the back between the first two stitches of the second piece of fabric and pull the yarn through. Return to the first piece of fabric and insert the tapestry needle from the right side to wrong side where the yarn comes out of the piece. Slip the tapestry needle upward under two horizontal stands and bring the needle through to the right side. Cross to the other side and repeat the same process, going down where you came out, under two strands and up. Continue working back and forth on the two pieces in the same manner for about an inch, and then gently pull on the yarn to snug the two pieces together. Continue until seam is complete, pulling seam closed every inch or so. Weave in the tail. Use the beginning tail to even-up the lower edge by working a figure 8 between the cast-on stitches at the corners. Insert the threaded needle from front to back under both threads of the corner cast-on stitch on the edge opposite the tail, then into the same stitch on the first edge. Pull gently until the “8” fills the gap.