A GPS from the chemistry set

Scientists teamed up to develop a chemical "processor" which reliably shows the fastest way through a City maze. As the method is basically faster than a satnav system, it could be useful in transport planning and logistics in the future, for instance, as the scientists report. You don't always need GPS, a map or a compass to find the right way. What demands a tremendous amount of computational power from today's navigation computers can also be achieved by taking advantage of the laws of physical chemistry and practicing so-called "chemical computing". The trick works as follows: A gel mixed with acid is applied at the exit of a labyrinth - i.e. the destination - filled with alkaline liquid. Within a shorttime, the acid spreads through the alkaline maze, although the majority of it remains together with the gel at the exit. When an alkaline solution mixed with dyes is now added to the other end of the maze, i.e. the entrance, it automatically seeks the way to the exit - the point with the highest acidity.