Wilson was unhappy with the basic concept of the Number 1 Lincoln Machine, and on 17 August suggested to Tritton the idea of using tracks that ran all around the vehicle. With d'Eyncourt's approval construction of an improved prototype began on 17 September. For this second prototype (later known as "HMLS Majesty's Land Ship "Centipede"", and, later still, "Mother"), a rhomboid track frame was fitted, taking the tracks up and over the top of the vehicle. The rear steering wheels were retained in an improved form, but the idea of a turret was abandoned and the main armament placed in side sponsons.