anchor.diff:      here h# 2000 w,
   ;
   
  -header-imm then
  +header-imm then     ( addr -- )
   : tthen
       here 2/
       swap +!
  
positive.code: header-imm do
  :noname
      do-common
      tbegin
      inline: >r
  ;
  
negative.code:         dup
      while
          dup @ swap        ( next leafptr )
          tthen
      repeat
      drop
      leaves _!
  