I just love stiles. I think they are so fascinating. They are intended to be a break in a fence that a human can go through or over, but an animal cannot. Ireland is full of them. I link the Wikipedia page below.

Stiles are usually steps that go over a fence. There are also what I think are called 'fence stiles' ----C-|--- shaped like that. The dash to the right of the C, swings inside the C. It's ingenious in that it is simple enough for any 4 year old human to use, but far too complicated for the average sheep.