See with your tongue. Navigate with your skin. Fly by the seat of your pants (literally). How researchers can tap the plasticity of the brain to hack our 5 senses — and build a few new ones. For six weird weeks in the fall of 2004, Udo Wächter had an unerring sense of direction. Every morning after he got out of the shower, Wächter, a sysadmin at the University of Osnabrück in Germany, put on a wi