#!perl $;="-";$;.=$"x3**$_.$;for$!..-1+pop;print"$; "
#!perl -l sub z{my$n=1/3*pop;$n>=1?z($n).($"x$n).z($n):"-"}print z 3**pop
#!perl -l $_="-"x($n=3**pop);$n/=3,s/(-{$n}){3}/$1.(" "x$n).$1/ge until$n<3;print