Stain is a set of a teacups designed to improve through use. This project examines the assumption that use is damaging to a product (For example, scratches on an iPod).

The interior surface of the cup is treated so as to stain more in predetermined places. The more the cups are used, the more the pattern is revealed. Over time they will build up an individual pattern dependent on the users personal way of drinking tea.

Find out more here. (via.)