<?php

class Father{
    protected  static $name = "father";
    public static function whoami_self(){
        echo self::$name."\n";
    }
    
    public static function whoami_static(){
        echo static::$name."\n";
    }
    
    public static function getInstance_self(){
        return new self();
    }
    
    public static function getInstance_static(){
        return new static();
    }
}

class FatherBrother extends Father{
    protected  static $name = "uncle";
}

FatherBrother::whoami_self(); //father
FatherBrother::whoami_static(); //uncle
var_dump(FatherBrother::getInstance_self()); //father
var_dump(var_dump(FatherBrother::getInstance_static())); //uncle