Hair tie
Challenge
Most commercially available solutions for tying a ponytail with one hand are either complicated or result in a ponytail that doesn’t hold well. This makes it unsuitable for sports, as the hair gradually comes loose and falls into the face.
Solution

Together with Heidi Ulm, Peter Stein developed a system from various prototypes that allows hair to be tied using one arm. The strength still needs to be slightly improved, and ideas are being considered for how to shorten the excess band.
Different hairstyles, such as a bun, are the long-term goal.
