Ad hoc grid with KeepLayout

grid

    GTButton *button0 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"top" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button1 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"1" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button2 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"2" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button3 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"3" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button4 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"4" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button5 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"5" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    GTButton *button6 = ({
        GTButton *button = [[GTButton alloc] init];
        [button setTitle:@"6" forState:UIControlStateNormal];
        [self.view addSubview:button];
        button;
    });
    
    
    NSArray *a1 = @[ button1, button2, button3 ];
    NSArray *a2 = @[ button4, button5, button6 ];
    NSArray *a = @[ button1, button2, button3, button4, button5, button6 ];
    
    KeepValue x = KeepRequired(20);
    
    a.keepAspectRatio.equal = KeepRequired(1);
    [a keepSizesEqualWithPriority:KeepPriorityRequired];
    [a1 keepHorizontalOffsets:x];
    [a2 keepHorizontalOffsets:x];
    [a1 keepHorizontallyAligned];
    [a2 keepHorizontallyAligned];
    
    button0.keepTopInset.equal = x;
    button0.keepHorizontalInsets.equal = x;
    
    button1.keepTopOffsetTo(button0).equal = x;
    button1.keepLeftInset.equal = x;
    button3.keepRightInset.equal = x;
    button4.keepTopOffsetTo(button1).equal = x;
    button4.keepLeftInset.equal = x;
    button6.keepRightInset.equal = x;