He hadn’t noticed at first, but the handle of her screwdriver was pitted with tooth-marks. Back on Earth, screwdrivers had evolved over his lifetime from wooden handles to plastic, and then to improved plastics that wouldn't be slippery when they were greasy, and they sometimes had rubber or plastic flocking overlaid on the handles to assist. Her tools were clearly designed to be comfortable in the mouth, soft enough to be gripped with teeth and strong enough to put up with it for years.