... In their seminal work on the Charade system, Baudel and Beaudoin-Lafon [6] note that one primary problem with midair gestures is that gestures are not self-revealing -the user must know the set of gestures that the system can recognize and their associated functionality. Most often, systems designed to teach mid-air interaction techniques require the use of additional hardware to reveal gestures to the user, usually in a visual [1,3,4,10,12,13,15,16,20,30,34,36,40], auditory [25,30], or haptic form [30,34]. Mirrored representations of the user are one common form of user training [1,3,4,12,13,20,31]. In terms of ubiquitous public display interaction, Vatavu suggested not requiring users to learn at all, but, rather, to use a preferred, familiar gesture set that is individual to each user. ...