A TARDIS interior micro-universe is created using Transcendental Equations that don't interface with Normal Space in a traditional way. The Default State a TARDIS interior includes an Environmental Metaphor created by the Hynoleptic Interface, which is responsible for the three dimensional form of the Pedestrian Infrastructure. Without the illusion of the Environmental Metaphor the interior TARDIS would be seen as a multidimensional bio-entity.
Thanks to their time brain,
Time Lords are able to function in this environment without significant problems. But the multi-dimensional
psychic
nature of the interior will drive lesser species mad with visions of sinuous and churning monstrosities. Non-sentient beings
(i.e. entities without proper biodata)
will only be mildly nauseous when viewing the interior without the Metaphor.
The Wallpaper Controls are used to alter the Environmental Metaphor's
Desktop Theme.
The color for the default interior is off-white. Since six is a very important number in Gallifreyan culture
the hexagonal form is a common structural shape in Gallifreyan architecture. Hexagons can be found in the shape of many consoles,
control rooms, and are often used to decorate the walls.
However, individual rooms (and perhaps the entire interior) can be remodeled quite quickly by changing the Desktop Theme. Coral (see illustration) and Leopard Skin are just two of the many options. It appears to take several months for the TARDIS to redecorate its console room.
Some customization is possible. For example, the hardness of the floors and walls are adjusted for the comfort of the crew.
The interior lights can be controlled from a switch on the console and can be raised to painful brightness. Operators who decide to paint the inside of the TARDIS should be careful as paint can easily jam a TARDIS's systems.
Since it is designed to function as something of a Safe Mode, the Secondary Control Room, desk-top theme can't be altered from default.