handshake (designed in collaboration with Jae Wan Park and Dong Ho Yun) - When people first meet and shake hands, the rings on the fingers get close enough to operate. The rings exchange their users information and stores them while they are shaking hands. So, the more people they meet, the more information they have. When the users browse through the people they meet, the card displays their basic information that was stored in the ring. The power source is provided from human tempurture, so it doesn't need any prug.