Inflatable book-mark

Designers Jung-Hyun Lee, Won-Sik Chae and Rhea Jeong have prototyped this "Abracadabra" bookmark that uses a little air-filled bladder to lift the page at the right spot. I think it'd fall out if placed at the page side, as shown here, but it would work pretty well if placed at the spine, in the crease of the binding.

Link