...is, for a good reason, similar to toddlers' crayon drawings/paintings. Because it has been created from the minds of toddlers. That is also why Death is powerless there, because toddlers cannot grasp the concept of death.
Hogfather, Terry Pratchett
Stock Object Colours: Discussed when Susan and the Oh God of Hangovers end up in the Tooth Fairy's country, which resembles a child's (toddler's) drawing. Susan realises what it is because (among other simplifications) the water in the creek is blue, the fish in the creek are bright orange, the treetrunks are plain brown, and the apples are bright red... even though creeks are usually transparent, freshwater fish are most often silver, treetrunks have a whole range of colors from brown to grey to green, and only some apples are red. But children draw brown treetrunks, orange fish, blue water, and red apples, because that's what they "know" they're supposed to be.
The Tooth Fairy Country has been created from the minds of young children (toddlers), and looks like a child's (toddler's) painting (think crayons). The sky is bright blue, the ground is bright green, the trunks of the trees are plain brown, all apples on those trees are bright red, and the river is a block of liquid blue through which orange cartoon fish swim. There are no variations in colour, or hues, or textures; everything is one colour. The sky does not extend as far as the horizon; in between the ground and the sky is an empty void. It is easy to see why the criminals hate it so much.
The childlike quality of the Tooth Fairy Country is beginning to affect the criminals, and they begin to revert further into infantile mindsets (fear of Poorly-Lit Pareidolia for Chickenwire, Oedipus complex for the Lilywhite brothers).
It is impossible to die in the Tooth Fairy Country-a little child (toddler) believes that dead people have just "gone away". Therefore, when someone dies, they disappear back to the Discworld. People who die in the Tooth Fairy's castle get teleported away. This is because the place is based on the imagination of children (toddlers), who do not really grasp the concept of death or what happens after you die.
Adaptation Distillation: The adaptation shows all the events as they happen chronologically, even those that Susan (and through her, the readers) does not learn about until almost the very end of the book (most notable are the relation between the Tooth Fairy's realm and children's ie toddlers' crayon drawings, how death is treated in the Tooth Fairy's realm, the outright spelling-out of Teatime's plan for the teeth starting with punching Banjo, and the no-longer-behind-the-scenes nature of Death's decision to impersonate the Hogfather).