I’ve three crowning gems; these are all that I wear. I order the peons to stop short and stare. I command the attention of all in the land - Three glittering gems in a long black band.

The clever description vividly portrays the familiar devices that manage the flow of vehicles and pedestrians every day. The "three crowning gems" refer to the distinct red, yellow, and green lights, each signaling a crucial command. These illuminated signals are indeed "all that I wear," as they are the primary visual component of the entire structure. When they change, they "order the peons to stop short and stare," compelling drivers and walkers to halt or prepare to proceed, thus commanding attention across the land. The "three glittering gems in a long black band" aptly describes the lights housed within their dark casing, typically mounted on a pole or overhead gantry.

The concept of traffic control signals dates back to December 1868, when the first manually-operated, gas-lit traffic signal was installed outside the Houses of Parliament in London to manage horse-drawn carriages. This early version, which used red and green lights along with semaphore arms, unfortunately exploded in 1869. The first electric traffic light was developed by policeman Lester Wire in Salt Lake City, Utah, in 1912, and installed in Cleveland, Ohio, in August 1914. It featured red and green lights and a warning buzzer. Expanding on this, William Potts, a police officer in Detroit, Michigan, created the first four-way, three-color traffic light in 1920, introducing the amber "caution" light we know today.

A significant advancement came from African American inventor Garrett Morgan, who patented his three-position traffic signal on November 20, 1923. His design included not only "stop" and "go" signals but also an all-directional stop that halted traffic from all directions, allowing intersections to clear and greatly enhancing safety. Morgan later sold the rights to his invention to General Electric for $40,000. From these early innovations, traffic lights have evolved into the complex, synchronized systems we rely on today, preventing countless accidents and maintaining order on our increasingly busy roads.