Here are some more double pages from the Souls sketchbook:
los gemelos (the twins), pages 61 & 62.
crease | Soul of the Machine, pages 63 & 64.
Soul of a Star, pages 65 & 66.
bug | Calling Dr. Rorschach, pages 67 & 68.
The last 3 images are "crease" drawings -- I'm calling them that in that they utilize the crease in between the individual pages in a deliberate manner.