my %tree = ( 'Is your animal larger than a breadbox' => { '1' => 'giraffe', '0' => 'cat', }, ); # anon hashref rather than array ref #234567890#234567890#234567890#234567890#234567890 sub f{ ($s,%t)=@_;$q=$s;do{{$v=a($q);$a=$t{$q}->{$v};$q= $a,redo if$t{$a};$q=$s,next if a($a);$n=&t;$o=i($a ,$n);$t{$o}={0=>$t{$q}->{$v},1=>$n};$t{$q}->{$v}= $o;$q=$s;}}while&w }