This refers to the transition from a square (čtyřkového, 1-2-4, 2+2) arrangement on a triangular (trojkové, 1-3) arrangements. An example is the reorganization of the american divisions in the period before the entry and after the entry of the USA into the second world war. Infantry division consisted until then of the two infantry brigades of two subordinate infantry regiments. The division, therefore, had four infantry regiments. When triangularizaci was brigadier level is cancelled and at the same time one regiment removed from subordination to the division. She had only three subordinate infantry regiments..