I just got a Norns Shield a few days ago and haven’t had much time to play with it (haven’t even coded one line) but I wanted to say that Sines is an excellent app. Thanks for sharing it.
It’s simple and elegant design and sounds wonderful. The only thing I wish it had is a key combo to modify sample rate and bit depth for a channel without going into the menus. Also, using an external MIDI controller to select the pitch for just one sine.
Well, I guess that’s a good motivation to write a bit of Lua myself 
Edit : and looking at the code I see that K1 already does what I wanted 