You want to try a little feature of the Windows Phone 8? If yes, and you have a Windows Phone 7 device, you can download an application called WPhone8 in the Marketplace. Microsoft's own applications provides a simulation of the homescreen like what OS they will come of it. You can not run this application through the simulator, but you can bring the application icon to Live Tiles, to resize and shuffle, as can be done on your Windows Phone 8. This is a good idea from Microsoft to familiarize users of Windows Phone 7 to WIndows Phone 8, but unfortunately the existing Windows Phone 7 now will not get the OS update, but just get a Windows Phone version 7.8 only.