We've shown you other cardboard tricks like this before, including how to use your phone's box as a stand, turn a suction cup into a phone stand, use one of those pizza box supports, even build ...

To make your own you will need a sheet of A4 cardboard, some sharp scissors or a craft knife, a printer and your iPhone dock cable that came with your 3G iPhone.

You can find detailed instructions on how to use it — and even make one for yourself — on Google's site. Google Cardboard looks like what you think it looks like: a piece of cardboard.