#!perl -l $a='-';$a.=$".$a,$"x=3for 1..pop;print$a
#!perl -l @s='-';@s=(@s,$",@s),$"x=3for 1..pop;print@s
#!perl -l s//-/;for$a(1..pop){s/.*/$&.$"x3**--$a.$&/e}print
#!perl -l sub _{my$v=pop;$v--?_($v).$"x3**$v._($v):'-'}print _ pop