The infantry and Airborne division structures commonly known as Pentomic divisions are actually two related organizations, officially known as Reorganization of the Airborne Division (ROTAD) and Reorganization of the Current Infantry Division (ROCID).
Shortly after the 101st began testing ROTAD, the CONARC began developing ROCID, forwarding the initial ROCID tables of organization to the Army Staff on 15 October 1956.