Wendy Gardiner answered:
Hi, the back of the twin needle stitching when sewing with a straight stitch is shown on the second lesson when discussing and using a twin needle. On the back of the work the bobbin thread connects the two top threads and looks like a loose zigzag stitch. If using different threads in the top, it can actually look quite pretty. I cover about 24 feet in this class, plus other aids such as the quilting guide.