anchor.diff:  
   header count
   : count
  -    dup 1+ swap c@
  +    d# 1 over+ swap c@
   ;
   
   header bounds
  
positive.code:     begin
          key?
      until
  ;fallthru
  : key>
      h# 1000 io@
  ;
  
negative.code:                             \ single number
      isvoid drop
      r> if negate then
  : return1
      d# 1
  ;
  