Designed by Won-Sik Chae, a bookmark using the movment of air, squeezing one side enflates the other side which enables the tube to lift up the pages of the book - making the user open the book more easily. The sticky side of the tube can be used like post-it. It contains an air-filled space, half of which is flattened by the weight of a book. Squeezing the exposed side inflates the hidden side lift the page just enough for your finger to slip in.

Or it could be arranged like a paper tree, just for fun. Quite interesting design.