“Interesting,” the
author says. From his pocket, he produces a piece of chalk.  He bends
forward, to touch the ground with it.  He then lifts it up to just
above his head, a white line following its progress, hanging in thin
air.  
“The principal is
simple,” he tells Raven.  “You draw a door in the air with the
chalk.”  He moves the chalk horizontally, a white line appearing in
its wake before he brings it down to touch the ground once more.  “It
is vital to remember to draw a handle,” he insists, drawing one. 
“And voilà!” he exclaims, gesturing at a white door which now
stands before him.  “After that, conventional rules of the Weave
apply.  Think about where you want to go as you open it.”

