The Octopus Symbols in the Book

I wanted to stay within the bounds of sort of hard, let's say, biology and try to figure something out that would be convincing to me as a reader. I came up with an idea of what an octopus might base its character system on or partially base it on. The symbols are, of course, integrated into the cover of the book. And then they come up in the text of the book itself. How did you decide on those particular symbols? So I made all of those symbols with like Microsoft Word,. And I kind of just made them up.