The highest ranks in each branch of the United State military, which are General of the Army for the Army, Fleet Admiral for the Navy and General of the Air Force for the Air Force, are designated by five 5-point stars in a pentagonal pattern. These ranks are reserved for wartime only.
In the Army, an upward pointing yellow chevron denotes the private E2 rank. The Marine Corps private first class insignia is a similar shape with a green field and red outline. The Army private first class insignia features the same chevron with an arc connecting the two bottom arms. The resulting field in the interior of the chevron and arc is colored black. As the ranks increase, the chevron and arc patterns are repeated to denote higher ranks.
A dark blue square with two and three diagonally inclined bars indicate the Navy's seaman apprentice and seaman, respectively. The petty officer's insignia features a red downward pointing chevron with a square dark blue field above it. An eagle with two crossed anchors is placed within this field. As rank increases, these chevrons are repeated below the insignia.
Officer insignias are more uniform across the branches of the military. For example, the insignia for captains in all branches is a double silver bar. Similarly, colonels are denoted by an eagle with a shield and bundle of arrows held by the talons.