Herringbone is a military formation where one member of the squad

Squad

In military terminology, a squad is a small military unit led by a non-commissioned officer that is subordinate to an infantry platoon. In countries following the British Army tradition this organization is referred to as a section...

 at the front faces forwards, then all members behind alternate facing left-right-left-right until the member at the back who faces backwards. When the squad moves the person next to the person facing backwards will tap the person facing backwards on the shoulder to make sure he is not left behind. This formation is performed mainly after crossing obstacle

Obstacle

An obstacle is an object, thing, action or situation that causes an obstruction. There are, therefore, different types of obstacles, which can be physical, economic, biopsychosocial, cultural, political, technological or even military.-Physical barriers:As physical obstacles, we can enumerate all...

s.