Looping is the core survivor skill in Dead by Daylight. The survivor runs circles around a solid object - a wall, a rock, a group of cars - so the killer, who is faster in a straight line, can never close the distance. The obstacle removes the killer's speed advantage entirely, because both players are covering the same circular path.
A loop ends when the killer forces a mistake, cuts the corner well enough to land a hit, or when the survivor runs out of resources at that structure and has to leave for the next one. Everything else in a chase is built on top of this: pallets, windows and mindgames all exist to extend or break a loop.
In a timed 1v1 duel, looping is essentially the entire game. There are no generators to do and nobody to save, so the survivor's only job is to keep the loop alive for as long as possible, and the killer's only job is to end it.