Techniques for presenting multiple content items on a display without hardware modification. These techniques determine a first angle relative to the display at which a first content item is to be shown and a second content item is to be hidden. The techniques also determine a second angle at which the first content item is to be hidden and the second content item shown. The techniques then compute a first pair of pixel values having a contrast that is less than a threshold at the first angle and a second pair of pixel values having a contrast that is less than the threshold at the second angle. The techniques then render the content items such that the first content item is perceivable at the first angle and hidden at the second angle, while the second content item is hidden at the first angle and perceivable at the second angle.