One of the best pieces of toy technology ever imagined is the decoder ring. Well what about having a kind of decoder ring for the world’s transportation systems, something you could wear that would get you a ride whether you were boarding a bullet train in Japan or the tube in London? As part of our recent visit to Boston we caught up with Chris Benson, who is working on just that with help from student inventors Edward Tiong and Olivia Seow in Singapore. Their product is called the Sesame Ring and its testing ground is Boston’s subway system, the T.