Homer Brooke was a machinist and mould maker with a particular interest in glass insulators. He was associated with various firms from the 1860's to the 1880's. At one point he crossed paths with the Chicago Insulating Co. whose CD 135's bear a lot of similar glass quality and moulding traits to these CD 120 ponies. This CD 120 can also be found embossed "PONY" with "PAT APP FOR" on the reverse, as well as the same without "PONY". My camera does not capture the vibrant "Brooke's Blue" of the far left piece well. Although a really stunning organic blue color, it is the most common color these are found in. The green is very rare, as is the light aqua. The dark teal-aqua is also a seldom seen color. These were found widely scattered over Kansas, Nebraska, and Colorado, states that were rapidly developing in the 1880's.