my $regs;

$regs->{1}{0}{0} = 1;

my $tree;

$tree->[0][0][0] = [
   [ 3, 0, 0 ],
];
 
$tree->[0][1][0] = [
   [ 0, 2, 0 ],
];

$tree->[1][0][0] = [
   [ 0, 3, 0 ],
];
 
$tree->[3][0][0] = [
   [ 0, 1, 0 ],
   [ 1, 0, 0 ],
];