sub d{print"\ec";select$q,$q,$q,0.3;for$p(0..2){printf"\e[%d;%dH%s".$/x$
d,$d-$_+2,2*$d*(1+$p)-($$p[$_]?(length$$p[$_])/2:1),$$p[$_]||"|"for 0..$
d-1}}push@0,"-"x(1-2*$_)for-($d=shift||3)+1..0;sub h{my($n,$s,$d,$i)=@_;
if($n>0){h($n-1,$s,$i,$d);push@$d,pop@$s;d;h($n-1,$i,$d,$s)}}h($d,0,2,1)