Here’s a really quick one.

Now we’ve got awesome self service machines in the Library which can print decent receipts, why not rearrange receipts to be a bit more useful? Presenting Receipt v2, which doubles as an awesome bookmark (if you just take out one book… not quite figured out two or more), shows you the due date at the top (so it’s sticking out) and includes a QR code for quickly grabbing more details or renewing.

This is standard 80mm receipt paper (although it would easily move to 70mm if that’s what the machines use) and QR codes are easily readable by all modern mobiles at that kind of scale. Should probably include a web link as well using the magic of Linking You.