TARDIS tight schedule, which led to Brachacki leaving the show due to disagreements with the production team and possibly a feeling that he had been given an impossible task. Despite his leaving the show and mixed reactions as to how the set looked (producer Verity Lambert liked it but director Waris Hussein did not), the basic design of the hexagonal console and wall roundels has persisted to the present day. In the Third Doctor serial "The Time Monster" (1972), the console room of the TARDIS was dramatically altered, including the wall roundels. This new set, designed by Tim Gleeson, was disliked
Power-law fluid which if both ends of the coupling are spinning at the same (rotational) speed, the fluid viscosity is minimal, but if the ends of the coupling differ greatly in speed, the coupling fluid becomes very viscous. Such couplings have applications as a lightweight, passive mechanism for a passenger automobile to automatically switch from two-wheel drive to four-wheel drive such as when the vehicle is stuck in snow and the primary driven axle starts to spin due to loss of traction under one or both tires. Just like a Newtonian fluid in a circular pipe gives a quadratic velocity profile (see