CoreAnimation.m

-(void)viewDidAppear:(BOOL)animated {
    
    
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:(CGRect){-50,-50,100,100}];
    // 0, 0 is center
    
    
    
    CAShapeLayer *shapeLayer = [[CAShapeLayer alloc] init];
    shapeLayer.path = path.CGPath;
    shapeLayer.fillColor = [UIColor orangeColor].CGColor;
    
    shapeLayer.position = self.view.center;
    [self.view.layer addSublayer:shapeLayer];
    
    CAKeyframeAnimation *shakeyShakey = [CAKeyframeAnimation animation];
    shakeyShakey.keyPath = @"position.x";
    shakeyShakey.values = @[ @0, @10, @-10, @10, @0 ];
    shakeyShakey.keyTimes = @[ @0, @(2/5.0), @(3/5.0), @(4/5.0), @1 ];
    shakeyShakey.duration = 0.4;
    shakeyShakey.repeatCount = 10;
    
    [shakeyShakey setValue:@"shakeyShakey" forKey:@"name"];
    
    shakeyShakey.delegate = self;
    
    shakeyShakey.additive = YES;
    
    [shapeLayer addAnimation:shakeyShakey forKey:@"passwordShake"];
}

-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
    NSLog(@"stopped %@", [anim valueForKey:@"name"]);
}