I'm captivated by this Timeline clock by Anthony Dickens.  It has made me think why the circular clock has become so accepted as the conventional interface used to portray time.  A circular clock reflects the cyclical nature of the sun or daylight, conveniently divided in half for those of us who can't count to 24.  I guess this works for the repetitive nature of most people's lives but it doesn't make a lot of sense when you think about the more general idea of time.  This Timeline clock is a much more literal translation of how we perceive time.  It shows past, present, and future in a linear manner, emphasizing the constant passing of time.  Where can I buy one?