<?php
class TestAutoload
{
    protected $foo;

    public function __construct($foo)
    {
        $this->foo = $foo;
    }

    public function load()
    {
        var_dump($this->foo);
        return false;
    }
}

$test1 = new TestAutoload('foo');
$test2 = new TestAutoload('bar');

spl_autoload_register(array($test1, 'load'));
spl_autoload_register(array($test2, 'load'));

new NonExistingCode();