Navigation apps can tell you how to get across town using only public transportation, but they don't make it a seamless experience. Wouldn't it be nice if you could pay for bikes, buses and trains from a single app? If Helsinki has its way, you might. The Finnish city plans to test a transportation mesh that will not only show you how to get from point A to point B using multiple public methods, but let you pay for it all in one shot through software or a website. A few companies will help launch the trial run in the Vallila neighborhood around the end of the year, with expansions to other areas over time.