Kryptos
The Berlin clock uses 4 lights below seconds for 5 hours each, and below that, 4 bars for 1 hour each (Uneven interval blocks).
On a not completely unrelated note, take a look at the coordinate projected on the other side of the plaza. Now look at the Kryptos. Something should be abundantly clear. If not, shine a light on it. Something I vaguely recall being used in ancient Greece and China.
SH