The design helps to comfort people longing for the deceased .In Eastern culture, water has spiritual power. There is a small pool on the base of the tombstone, which can be filled with water. Under the pool there is an ultrasonic vibration device that makes water ripple. The strength of the ripples changes with the pitch of the voice from the mourner. The sensor can detect the slight changes when the mourners are speaking, and then activates the vibration of water ripple with these changes, as if the interaction comes from heaven.