TARDIS 2005–10, the roundels are built into hexagonal recesses in the walls. Ever since the TARDIS was redesigned at the beginning of the 2010 series, there have been a range of different roundel designs around the console room. These include circular holes that are recessed deep into the walls, hexagonal holes that are lit from behind each face, round indents with brass rings around the outside, and a glass centre that is illuminated blue. In "The Day of the Doctor", when the TARDIS' control room briefly appears as the War Doctor's room, the Eleventh Doctor points out to the Tenth Doctor
Static spherically symmetric perfect fluid Static spherically symmetric perfect fluid In metric theories of gravitation, particularly general relativity, a static spherically symmetric perfect fluid solution (a term which is often abbreviated as ssspf) is a spacetime equipped with suitable tensor fields which models a static round ball of a fluid with isotropic pressure. Such solutions are often used as idealized models of stars, especially compact objects such as white dwarfs and especially neutron stars. In general relativity, a model of an "isolated" star (or other fluid ball) generally consists of a fluid-filled interior region, which is technically a perfect fluid solution of the Einstein field