15thc perception on swallowtail merlons?

[R. Sale]

Interesting, and as you noted, something that was a transplant of sorts.

Also look at the details of the merlons. A swallowtail merlon has an outer edge that is straight vertical from top to bottom. These merlons change direction at the top. Also, I believe I see an example of light coming through at the base of one of the merlons. It is almost possible to imagine that these merlons are each a representation of a mini fortress showing two joined towers with pointed roofs, but it's a bit too hazy.