tiny_tree.php

<?php
echo('<pre>');
function p($i, $l){
	for ($x=0;$x<$l; ++$x){
		echo(chr($i));}
}

function mk_tree($h=5){
	$i=0;$h=1<<$h;$b=$h;
	while ($b>1){
		$b=$b/2;
		for ($i=$b?$h/$b:0;$i;$i--){
			p(32,$b-1);p(!($i%2)*32+32,1);}
		p(10,1);
	}
}

mk_tree();
echo('</pre>');