Estoy tratando de crear un camino bezier como el triángulo de instagram en la imagen a continuación, sin embargo, debo estar haciendo algo mal. ¡El camino de Bezier no se muestra!

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.

}

-(void)viewDidLayoutSubviews{
[super viewDidLayoutSubviews];

[self drawTriangle];

}

- (IBAction)closeButton:(UIButton *)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}

- (void)drawTriangle{

UIBezierPath* trianglePath = [UIBezierPath bezierPath];
[trianglePath moveToPoint:CGPointMake(self.signUpButton.center.x, self.signUpButton.frame.origin.y + 30)];
[trianglePath addLineToPoint:CGPointMake(self.signUpButton.center.x - 10, self.imageView.frame.size.height)];
[trianglePath addLineToPoint:CGPointMake(self.signUpButton.center.x + 10, self.imageView.frame.size.height)];

UIColor *fillColor = [UIColor whiteColor];
[fillColor setFill];
UIColor *strokeColor = [UIColor whiteColor];
[strokeColor setStroke];

 [trianglePath fill];
[trianglePath stroke];

[trianglePath closePath];
}