|Trabb Pardo–Knuth algorithm

a : 11 0

 i
 if i LE 10
    [] $s
    ~ $s w
    w a.i
   + i
    goif
 endif
 10 i
 if i GE 0
    call f
    if x GT 400
       'too large' $s
    else
       ~ x $s
    endif
    ~ i $r
    + ' ' $r
    + $r $s.1
    $s []
    - i
    goif
 endif
 stop

f a.i t
  * t t x
  * x t x
  * 5 x
  abs t
  sqrt t y
  + y x
  return