I would give this app a 5 if it weren't for the infernal noise when you punch the buttons. It's so god awful there are no words for it. It's anything but soothing and meditative.
I've looked for preferences to turn it off, and if I've missed them, I apologize, but man ... I'm not sure who told the developer, "oh, sure, make the buttons click and beep and make it as loud as you can.".
Give us a way to turn that racket off and I'll gladly update my review. But until then, it's really disappointing because the app itself is very cool, but unless I turn all my iPad sounds off completely, I can't even use it laying in bed because it will wake my husband up.