algol apa ini?

<?php
$num= isset($_GET['i'])?$_GET['i']:2;
$result=array();
$raw=algol($num,$result);
echo '<pre>'.print_r($result,1).print_r($raw,1);

function algol($num,&$result){
    $q=array();
    $ar=array();
    $result[]="memory:".memory_get_peak_usage();
    echo "<hr>$num";
    if($num==1){
        $format="%s";
        $result[]="q=";
        $qx="x";
    }
    else{
        $raw=algol($num-1, $result);
        //print_r($raw);
        $qx="x".implode(",x",$raw);
        $result[]="q=".implode(", ",$raw);
    }

    $result[]="num:$num";
    $result[]="q(x):$qx";

    if($num==1){
        $q0=sprintf($format,0);
        $result[]="q(0):$q0";
        $ar[]=$q0;
    }
    else{
        $str="";
        foreach($raw as $v){
            $str.=$ar[]="0".$v;
            $str.=",";
        }
        $result[]="q(0):$str";
    }

    if($num==1){
        $q1=sprintf($format,1);
        $result[]="q(1):$q1";
        $ar[]=$q1;
    }
    else{
        $str="";
        foreach($raw as $v){
            $str.=$ar[]="1".$v;
            $str.=",";
        }
        $result[]="q(1):$str";
    }
    $result[]="q=".implode(",",$ar);
    return $ar;
}