This Sticker Adds Four Customisable Buttons to Your Android Device
Check this out!
http://media.gizmodo.co.uk/wp-content/uploads/2014/04/snxwwf8gd6tnrxito0al.jpg
I think it’s an interesting concept and a good use of the (somehow forgotten) NFC technology.
http://www.gizmodo.co.uk/2014/04/this-sticker-adds-four-customizable-buttons-to-your-android-device/