Refinements to the treatment. 
Coils They may be wound in more than one revolution. However, try to keep the total area of the coils proportional to the central area. A good proportion is 1/3:2/3 of the radius; [central area should be twice that of coils] centre:coils, 2:1. The more coils in the spiral, the narrower will be the path between them, or else the larger the radius. With a square-cut or straight nib, you must allow for thicks and thins. Avoid this tendency. Double spiral, c-scroll. the border ends in a single spiral.
   
next: issue 6