<?php

class x
{
    public function abc()
    {
        print __METHOD__ . "\n";
    }
    static function sabc()
    {
        print __METHOD__ . "\n";
    }
}
$a = new x();
$a->abc();
// OK
$a->sabc();
// Possible but weird
x::abc();
// Should not be possible but actually is
x::sabc();
// OK