Two prototypes of the slotted Donald Deskey lamppost were installed at Broadway and Murray Street on opposite corners near City Hall in 1958.
Besides being the first appearance of this now-iconic NYC lamppost, this also marked the first appearance of the GE M400 luminaire, which burned greenish-white — a contrast to the warm yellow incandescents which preceded them.
These were just prototypes, and when Deskeys finally got installed on a widespread basis in 1964, the curve on the mast was a bit gentler and there was less of an L-shape, though this post actually survived till after 2000. It was finally replaced by a stylized retro Twinlamp specially made for Broadway outside City Hall Park.