File this under “I wish I had thought of that.”

Last year, two MIT students won a prestigious international design award for a novel idea: Turn footsteps into electrical energy. The proposal imagined that an Italian train station would install a special floor. As passengers raced to catch their trains, the energy in their stomps would feed through an electrical system and power the building’s lights. Cool idea, but it only existed on paper.

A year later, Tokyo is rolling out the real thing. The East Japan Railway Company will be testing “power-generating floors” in ticket gates and staircases. As people move through the gates, they’ll step on stone tiles that give a little under the weight. That slight movement is captured and turned into energy. You can learn more about the process, called piezoelectric conversion, in a Monitor article from last year.