I recently got to know  a new use of static keyword.
I can also refer to the current class using
statickeyword.
So, say I have below class.
class X {
         static $x = 'Hello World!';
         public function greet(){
              return static::$x; //Or self::$x           
              }
         }
As, I can access $x both ways using static::$x and self::$x.
So, Is there any difference betwen them? I can use them interchangeably or There is some cases they behave differently?