Jagged window 
   on the world:
 All light and sound
   deadened,
   but from one opening --
 The cave mouth.

From behind
   nothing stirs,
      nothing glows,
   shadows are subsumed
      by shadow.

 Eyes and mind
   frame the cave mouth,
   making the mind
      a cave within a cave:
         layered silence
         layered remoteness,
      and all input of a single,
         common source.

How many caves deep might
   this thing go?