If you have a Nintendo 3DS (which does have cameras), you can use QR codes to inject custom content into your copy of the game. Note: This requires a modded/homebrew-enabled 3DS.
Using the popular 3DS homebrew file manager, FBI , users can bypass connecting their handheld to a computer by scanning a generated QR code. mario kart ds qr code
In practice, most QR codes you see link to a .duc (DS save file) or a patch file. Scanning the QR with your phone just reveals a download URL. If you have a Nintendo 3DS (which does