     min-depth max-depth 2 <range> [| depth |
         max-depth depth - min-depth + 2^ [
             [1,b] 0 [
-                [ depth ] [ depth neg ] bi
-                [ bottom-up-tree item-check + ] 2bi@
+                dup neg
+                [ depth bottom-up-tree item-check + ] bi@
             ] reduce
         ]
         [ 2 * ] bi


    "long lived tree of depth " write max-depth pprint
    "\t check: " write item-check . ;

: stretch-tree ( max-depth -- )
    1 + 0 over bottom-up-tree item-check
    [ "stretch tree of depth " write pprint ]
    [ "\t check: " write . ] bi* ;

:: long-lived-tree ( max-depth -- )
    0 max-depth bottom-up-tree
