How to do Interlaced Sprang

how to make a scarf based on Peter Collingwood's book The Techniques of Sprang, section 7.1, Over One, Under One Interlaced Sprang. Sprang interlacing makes threads cross in the fabric, like the way your shoelaces cross. When you use a warp with lots of colour, you get an effect something like argyle. The threads twist around each other clockwise in row 1, a twist which looks like the letter Z, and then in row 2 the threads twist counterclockwise, a twist which looks like the letter S. You can see a