MacStories features a fantastic tech demo today that shows glasses-free 3D working on the iPad 2. The video was made by Jeremie Francone and Laurence Nigay from the Laboratory of Informatics of Grenoble at the EHCI Research Group, and shows how they achieve glasses-free 3D by using head-tracking technology courtesy of the iPad 2?s front-facing camera combined with basic 3D graphics. According to MacStories, the glasses-free 3D experience doesn?t even need the iPad 2?s accelerometer to work, being based solely on the camera and the movement of the user?s head as they look at the screen. This is shown in the video by how the on-screen graphics change depending on the position of the user, giving the illusion of 3D. As MacStories notes, Nintendo has used glasses-free 3D for its new 3DS handheld (albeit with some customers complaining of motion sickness after using the device), and there has also been speculation in the past that Apple might be thinking of building glasses-free 3D capabilities into the iPod touch.