How to abuse PHP's implementation of object privacy to do what you want.

TestAbusingPHP

<?php

class TestAbusingPHP
{
        public $property;

        private function Write()
        {
                echo '#' . $this->property . '#';
        }

        public function Abuse($variable)
        {
                $abuser = new TestAbusingPHP();
                $abuser->property = $variable;
                $abuser->Write();
        }
}

$a = new TestAbusingPHP();
$a->Abuse('test');