six shades of white

The clock in the South Towe rof the Wrigley Building in downtown Chicago  is two stories high. The shape of the tower is patterned after La Giralda, once a minaret, now part of Spain’s Seville Cathedral.
It took 250,000 terra-cotta tiles to clad the two towers.  The tiles are occasionally hand-washed to keep them bright.
The tiles are six shades of white, from blue-white at the bottom to creamy-white at the top, so the building looks brighter as it rises.