Hi again Thomas, and sorry for the late reply.
It seems silly now that I understand what you meant, I never thought about giving direction to the waves when I was implementing them but sounds like a natural addition, I've added this to the roadmap and I'll add it to the app as soon as I can. It might take a bit of time, as I'll have to change the way it works now, without breaking old save files, but it will come. :)