The T-Patch was first used during the First World War.
The Division was composed of men from the Texas and Oklahoma
National Guards and the original choice of design was the
Lone Star for Texas and the Indian Head for Oklahoma.
However, that insignia was adopted by the 2nd Infantry and
the 36th chose the T-Patch instead in 1918.
The T-Patch is in the shape of an arrow head to symbolize
Oklahoma and sports a large "T" for Texas.