While a shadow creeps along we witness the rotation of the earth
. They (The Hours) could be seen as an exploded view of a sundial, with all their parts (the hours) spread throughout the gallery. In this way time is stretching out threw space while the building itself is turned into a clock-body. Employing sunlight by using both the shadows casted by the architecture — and the light reflecting off of some precisely angled mirrors on tripods. Who (the light and shadows) on their terms interact with the dial parts: casted arrows, numbers and gnomen in aluminium and bronze. The different colours of these two conductive metals are used to layer information and make multiple readings of this clock-like-work possible. 
Interactions with light and shadows at both set and unset times, and probably some days not at all.