They really are the coolest ever but until you really get used to stitching them they can be a torment.
There are two ways I can diagram a Jessica. The top is how most people present a diagram for a Jessica. It shows all the stitches. They are numbered. You can see that the final stitch goes under the beginning stitches so that when it is finished it is a continuous flow. You can't easily find the stop and start points.