PHP Abstract Factory Pattern Implementation

I am reading about the different patterns available out there. Currently I am on the Abstract Factory Pattern and I think I have a pretty good grasp on it. My resources are, besides wikipedia: http://ift.tt/1wDERKg http://ift.tt/1wdkJhj http://ift.tt/1xL2GFu

I am using Apple and its products to make a sample Abstract Factory pattern as an example. I understand that code duplication is bad design, hence the reason I am writing this. My code so far is:

abstract class AbstractAppleFactory {
    abstract public function createiPod( $capacity, $type, $color, $engraving );
    abstract public function createiPhone( $capacity, $type, $color, $antenna );
    abstract public function createComputer( $type, $HDCapacity, $CPU, $ram );
}

class iPodFactory extends AbstractAppleFactory {
    public function createiPod( $capacity, $type, $color, $engraving ) {
        $class = 'iPod' . $type;

        return new $class( $capacity, $color, $engraving);
    }

    public function createiPhone( $capacity, $type, $color, $antenna ){ /* no implementation necessary */}
    public function createComputer( $type, $HDCapacity, $CPU, $ram ){ /* no implementation necessary */}
}

interface iPlayer {
    public function play();
    public function stop();
    public function fastForward();
    public function rewind();
}

abstract class iPod implements iPlayer {
    protected $capacity;
    protected $color;
    protected $engraving;

    public function __construct( $capacity, $color, $engraving = null ) {
        $this->capacity = $capacity;
        $this->color = $color;
        $this->engraving = $engraving;
    }
}

class iPodClassic extends iPod {
    public function play() {/* implementation goes here */}
    public function stop() {/* implementation goes here */}
    public function fastForward() {/* implementation goes here */}
    public function rewind() {/* implementation goes here */}
}
class iPodShuffle extends iPod {
    public function play() {/* implementation goes here */}
    public function stop() {/* implementation goes here */}
    public function fastForward() {/* implementation goes here */}
    public function rewind() {/* implementation goes here */}
}

etc. etc. There is just too much code to put on here. I know that it is better to organize in directories and namespaces. That is not what I am learning right now. I am learning about patterns and OOP concepts.

The section in question is:

class iPodFactory extends AbstractAppleFactory {
    public function createiPod( $capacity, $type, $color, $engraving ) {
        $class = 'iPod' . $type;

        return new $class( $capacity, $color, $engraving);
    }

    public function createiPhone( $capacity, $type, $color, $antenna ){ /* no implementation necessary */}
    public function createComputer( $type, $HDCapacity, $CPU, $ram ){ /* no implementation necessary */}
}

Due to inheritance/abstraction I am forced to implement two unnecessary methods in an unrelated factory. createiPhone() and createComputer(). Am I doing the Abstract Factory Pattern right? Again, "code duplication is bad design!" What better way is there to go about this?