Could it be that this represents a system for generating music?

[Bluetoes101]

And then, I find myself asking: what exactly *is* a "root"? The answer is that it isn’t actually a plant root. So, what is it, then? Well, it’s something that looks exactly like a plant root.

In other words, what has been depicted here is something that bears a striking resemblance to a root.

So, if it looks like a root and walks like a root... is it a duck?

and therefore?.. 
a witch! 

In all seriousness though (OP), a lot of the roots are intentionally made to look like animals, people, faces etc. Other manuscripts do this too.