Rotate an Image, Another One Appears

Hidden elements can now be placed into an inkjet printed image, thanks to EPFL software. These hidden elements become visible by simply rotating the print. Hide an image within an image. EPFL scientists have developed a printing algorithm that does just that onto metallic sheets. Two images are printed together using an inkjet printer so that only one image can be seen at a time from a given angle. The technique could one day be used as a security element in passports and printed money to prevent counterfe