According to the venerable Chogyam Trungpa Rinpoche's teachings, the Sanskrit seed syllable HUM is the sound connects with "energy"; HUM represents "the state of meditation when awareness breaks out the limits of ego." "HUM is the energy of the universal force that transcends the limitation of ego, or rather, pierces through the wall of ego."
Calligraphy: "HUM". Sumi ink on rice paper, mounted on paper. The size is 11 by 15 in. The seal is "Buddha's Heart".