Magical law of "containment"

Strange magical barriers that fold space back upon itself creating a loop that puts travelers back where they started in the lands. Such barriers have been seen in Daventry, Kolyma, Llewdor, and even Tamir.

Real World
Note that at least in some cases, the phenomenon can be explained by saying that the land is in fact an island, and the character only walks and makes cicles across its shores. Imagine for example Llewdor as an island with the desert on its centre, and Gwydion walking around it. However it doesn't quite work entirely since it would leave circumferance of the island much smaller than the endless desert on the inside. It should also be noted Llewdor is actually on a continent connected to Tamir with the desert and the death bog in between, both lands make up 2 of the main kingdoms of Tanalore.