Just tried it, it's just a pitch adjustment. A fine start, but I wouldn't call it "powerful". Even old versions of this kind of thing are far more varied, eg:

Just tried it, it's just a pitch adjustment. A fine start, but I wouldn't call it "powerful". Even old versions of this kind of thing are far more varied, eg: https://www.youtube.com/watch?v=sz53Dk37m-0 https://www.youtube.com/watch?v=sz53Dk37m-0 It's easy to try, just clone and run ./lyrebird, it runs right from the tree.