It was originally a pagan thing, but was redone to fit the theme of Christianity and is now typically used as a tile pattern in churches. There is no standard design or anything like that for it either, as it was adapted by many artisans and made into more of a style than anything.
In this context, it is likely just a design choice though. It doesn't really mean anything to anyone anymore.
Yes.
It was originally a pagan thing, but was redone to fit the theme of Christianity and is now typically used as a tile pattern in churches. There is no standard design or anything like that for it either, as it was adapted by many artisans and made into more of a style than anything.
In this context, it is likely just a design choice though. It doesn't really mean anything to anyone anymore.
Example: http://img0.etsystatic.com/008/0/5139449/il_340x270.398234326_o865.jpg
A less obvious example: http://img1.etsystatic.com/000/2/6605354/il_340x270.342976745.jpg
I could be wrong though. If someone else, especially someone on the art team, has something else to say about it, please do.