Early architects paid much attention to the relationship between space and time: the earliest buildings had structures linked to the cycle of the heavenly clock. Indeed, the notion of time emerges naturally from the diurnal rise and fall of the Sun as well as the more leisurely progression of the seasons. Space, on the other hand, is defined by the relationship between objects, implicit as a void. What is more, there is no natural scale, no spatial equivalent of the length of the day.