This represents how time is expressed in ASL and how the distance from your body can express the changes in time. For example, 1H is one hand, 2H is two hand, present tense happens closest and in front of the body, future is in front of the body and the past is to your back.
Por ejemplo, 1 hr. es una mano, 2 hrs. es dos manos, el presente se hace más cerca y en frente del cuerpo, el futuro es en frente del cuerpo y el pasado es en la espalda.