Tyson has three types of towels in his airing cupboard: red, blue, and purple. The blue are for Lily, her white coat means she needs to be cleaned often to keep it white, which is the same reason why Bobby has his own towels, the red ones. The towels Tyson uses to dry himself are the purple towels because he is, on occasion, pedantic and would rather not get covered in dog hair straight out of the shower.