When the last bar is woven, insert the needle from back to front in the corner fabric at the first junction(A). Move to the next junction and insert the needle in and back out, leaving a 2 x 2 fabric square in the center (B).
At the first corner, bring the needle from back to front in the center satin stitch. Bring needle out on the left side of the extended thread to form the twist in the thread before continuing to the next fabric junction (C).
Work around the outside of the space in the same manner, inserting the twist in every corner (D).
When back at the starting point, insert the needle into the first junction and run the thread beneath several satin stitch blocks before trimming off (E).