My iPhone app has two boxes with content. When user switch the orientation of a phone boxes change the position like this:

Portrait

```
|---------|
| BUTTON1 |
| BUTTON2 |
|---------|
|         |
| BUTTON3 |
| BUTTON4 |
|         |
|---------|

```

Landscape

```
|---------|---------------|
| BUTTON1 |    BUTTON3    |
| BUTTON2 |    BUTTON4    |
|---------|---------------|

```

What is the right way to go? Two XIBs, other tricks? Should I resize elements manually in code?