2.3 Symmetry

Some body parts such as hands, eyebrows and corners of the mouth consist of a pair of members, so that theoretically gestures can be carried out with only one of the body parts or both. Furthermore, when both body parts move, they can do so independently or simultaenously. When moving simultaneously, they can do so in parallel (for example, both hands move to the right of the speaker) or in a mirror-imaged fashion (for example, in making a circular gesture the right hand moves to the right and the left hand to the left).