title: iOS: I want to continuously rotate an image, but it doesn't work
body: <p>Have the code from several examples on stackoverflow. But my image doesn't rotate..any idea why? It is displayed on the screen, but fixed..</p>
  
  <pre><code>-(UIImageView *)movablePropeller
  {
      if(!_movablePropeller){
          _movablePropeller = [[UIImageView alloc] initWithFrame:self.frame];
          _movablePropeller.image = [UIImage imageNamed:@"MovablePropeller"];
          [self addSubview:_movablePropeller];
      }
      return _movablePropeller;
  }
  
  - (void)startPropeller
  {
      CABasicAnimation *rotation;
      rotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
      rotation.fromValue = [NSNumber numberWithFloat:0.0f];
      rotation.toValue = [NSNumber numberWithFloat:(2 * M_PI)];
      rotation.cumulative = true;
      rotation.duration = 0.7f; // Speed
      rotation.repeatCount = INFINITY; // Repeat forever. Can be a finite number.
  
      [self.movablePropeller.layer removeAllAnimations];
      [self.movablePropeller.layer addAnimation:rotation forKey:@"Spin"];
  }
  </code></pre>
  
  <p>(and of course I would love to have it in a seperate thread, not to block the UI)</p>