gistfile1.m

UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];
    button1.translatesAutoresizingMaskIntoConstraints = NO;
    button1.backgroundColor = [UIColor greenColor];
    [button1 setTitle:@"button1" forState:UIControlStateNormal];

    UIButton *button2 = [UIButton buttonWithType:UIButtonTypeCustom];
    button2.translatesAutoresizingMaskIntoConstraints = NO;
    button2.backgroundColor = [UIColor redColor];
    [button2 setTitle:@"button2" forState:UIControlStateNormal];

    UIButton *button3 = [UIButton buttonWithType:UIButtonTypeCustom];
    button3.translatesAutoresizingMaskIntoConstraints = NO;
    button3.backgroundColor = [UIColor yellowColor];
    [button3 setTitle:@"button3" forState:UIControlStateNormal];
    
    [self.view addSubview:button1];
    [self.view addSubview:button2];
    [self.view addSubview:button3];
    
    NSDictionary *viewMap = NSDictionaryOfVariableBindings(button1, button2, button3);
    
    NSDictionary *hmetrics = @{@"width" : @(106)};
    
    NSArray *hConstraints =
    [NSLayoutConstraint constraintsWithVisualFormat:@"H:|[button1(width)][button2(width)][button3(width)]|"
                                            options:kNilOptions
                                            metrics:hmetrics
                                              views:viewMap];

    [self.view addConstraints:hConstraints];
    
    NSDictionary *vmetrics = @{@"height": @(100)};
    
    NSArray *vConstraints1 =
    [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[button1(height)]"
                                            options:kNilOptions
                                            metrics:vmetrics
                                              views:viewMap];

    NSArray *vConstraints2 =
    [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[button2(height)]"
                                            options:kNilOptions
                                            metrics:vmetrics
                                              views:viewMap];
    
    NSArray *vConstraints3 =
    [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[button3(height)]"
                                            options:kNilOptions
                                            metrics:vmetrics
                                              views:viewMap];
    [self.view addConstraints:vConstraints1];
    [self.view addConstraints:vConstraints2];
    [self.view addConstraints:vConstraints3];