ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (IBAction)middleButtonTapped:(UIButton *)sender {
    [UIView animateWithDuration:0.5 animations:^{
        sender.layer.cornerRadius = sender.frame.size.height / 2;
    }];
}


@end