Why do other forts resemble Gibraltar's works?

Is Fort Loudoun's resemblance to Gibraltar a coincidence or the result of shared design ideas?

Much of the resemblance is attributed to William Green's writings and to the engineers who learned under him.

The resemblance is presented as the product of professional transmission rather than simple chance. Green wrote about his methods, trained other engineers, and learned within a wider community of military practice. Officers who absorbed those lessons carried related solutions to other fortifications. Gibraltar therefore matters not only as one successful fortress but also as a site from which engineering knowledge circulated.