I thought about this for a couple of days, knowing there is no clear-cut answer and we all have opinions.
Undoubtedly, there are a few people in the faceting world who are unscrupulous and want to publish a slightly modified version of someone else’s work as their own. Just changing a design via tangent ratio to match the material does not seem to me to be illegal. However, publishing the work as one’s own is, in my opinion, the lowest form of “design”.
For example, if I put a mustache on the Mona Lisa, it’s still the Mona Lisa… just not my work.