.runstdin dup 9 mul 6 sub dup -1 0{2 copy sub 1 index max 1 sub 3 idiv 3 index
2 mul sub 2 add 0 max dup{(   )print}repeat -2 mul 3 index 3 mul add 2 sub exch
3 mod 0 eq{{( ##)print}repeat/}{{(#  )print}repeat/#}ifelse =}for