<?php

class x {
    const a = -1;

    static function create() {
        return self::a;
    }

    static function create3() {
        return static::a;
    }
}

class y extends x {
    const a = 1;

    static function create2() {
        return self::a;
    }
}

echo y::create();
echo y::create3();

?>