objective-c - cycling randomly through animations on button

Question

I have an app that currently rotates a button (image) twice when pressed. I'm wanting to cycle through scaling the button and also shaking the button. So the three animations would be: Scale, translate, rotate. How can I cycle through these randomly? Here's what I currently have for the button:

- (IBAction)playAudioAction:(id)sender {
    UIButton *btn=(UIButton *)sender;

    CABasicAnimation *fullRotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
    fullRotation.fromValue = [NSNumber numberWithFloat:0];
    fullRotation.toValue = [NSNumber numberWithFloat:((360*M_PI)/180)];
    fullRotation.duration = 0.5;
    fullRotation.repeatCount = 2;
    [btn.layer addAnimation:fullRotation forKey:@"360"];

    [self playAudioOfType:btn.tag];

}