TARDIS to those first seen in 1963, with multiple roundels illuminated from behind. The fourth major redesign of the TARDIS in the revived series appeared in the eleventh series. New production designer Arwel Wyn Jones said that the inspiration for the Thirteenth Doctor's TARDIS was based on the 2005-10 model, which he had worked on. The console room is the "safest place on the ship," and so when its occupants are in danger the TARDIS will reinvent its architecture so as to allow them to enter the console room. This can also result in the TARDIS materialising itself within its own
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