Zend Exam 200-710 Topic 2 Question 64 Discussion

In the following code, which classes can be instantiated?

abstract class Graphics {

abstract function draw($im, $col);

}

abstract class Point1 extends Graphics {

public $x, $y;

function __construct($x, $y) {

$this->x = $x;

$this->y = $y;

}

function draw($im, $col) {

ImageSetPixel($im, $this->x, $this->y, $col);

}

}

class Point2 extends Point1 { }

abstract class Point3 extends Point2 { }