Overlapping images in cocoa touch applications

I programatically created a box. It can be moved around the screen. The problem is that there are buttons on the screen I made in Interface Builder. When the box moves over a button, it covers the开发者_StackOverflow button. How can I make it appear behind the button?

When you add your box to the view, instead of using [view addSubview:box] use [view insertSubview:box atIndex:0].