Stop Moving object. If statement causing problems. (Objective-C)

I am working on my first project in objective-c and I am trying to make an object (that I have coded to move right) run code for the end of the game once it reaches a certain point. I run my app and the object just keeps moving right with no stop. I need to know what I need to do so that game over runs once the object reaches the given point. Any help would be greatly appreciated. I am just getting started with my first project so it is probably something very simple and obvious but I just have not been able to find the answer to my problem anywhere. Again Thanks.Here is my code.

        #import "Game.h"

    @interface Game ()

        @end


        @implementation Game

        -(IBAction)Play:(id)sender{


        PieceMovement = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(PieceMoving) userInfo:nil repeats:YES];

        Play.hidden = YES;

    }

    -(void)GameOver{
        Leave.hidden = NO;
        [PieceMovement invalidate];
    }



    -(void) PieceMoving{
        Piece.center = CGPointMake(Piece.center.x +5, Piece.center.y);

        if (Piece.center.y == 200) {
            [self GameOver];
        }

    }
    - (void)viewDidLoad{
        Leave.hidden = YES;

    }


    @end

-------Game.h

#import <UIKit/UIKit.h>

@interface Game : UIViewController

{
    IBOutlet UIImageView *Piece;
    IBOutlet UIImageView *Chunk;
    IBOutlet UIButton *Play;
    IBOutlet UIButton *Leave;



    NSTimer *PieceMovement;


}

-(IBAction)Play: (id)sender;

-(void)PieceMoving;
-(void)GameOver;

@end

--------Game.h

#import <UIKit/UIKit.h>

@interface Game : UIViewController

{
    IBOutlet UIImageView *Piece;
    IBOutlet UIImageView *Chunk;
    IBOutlet UIButton *Play;
    IBOutlet UIButton *Leave;



    NSTimer *PieceMovement;


}

-(IBAction)Play: (id)sender;

-(void)PieceMoving;
-(void)GameOver;

@end