PHPの静的メソッドは非静的メソッドにアクセスできますか?

<?php
class test{
    function test() {
        echo &#39;it works&#39;;
    }
}
test::test();
?>

Fatal error: Non-static method test::test() cannot be called statically in /home/×××/test.php
on line 7 Call Stack: 0.0002 332548 1. {main}() /home/×××/test.php:0

<?php
class test {
    function test() {
        echo &#39;it works&#39;;
    }
    function test2() {
        echo &#39;it works too&#39;;
    }
}
test::test2();
?>

it works too

<?php
class test{
    static function test() {
        echo &#39;it works&#39;;
    }
}
test::test();
?>

Fatal error: Constructor test::test() cannot be static in /home/xxx/test.php on line 9

Cannot make a static reference to the non-static method showString() from the type HelloWorldApp