wikipedia poem, no. 38 [anatomic brief history, 3]

three

SIGABA  devised one thousand years ago
a tape-related19th century relative of
  position and gene 
the U.S. 
in office wired 
its migrations 
once for 
  the 
showing and once again well into the 1940s  In 
   1943 an unknown major general
       put to the 
the German command 
  a reading of Laurance Foreknown 
by which Axis forces
realized 
      the Navy chiffre