It's just a shame that you can't save your musical masterpiece, in Grantophone for Windows 8. This virtual instrument is a hybrid of a piano keyboard and a theremin. If you've no idea what that is, it's the instrument used to create the music for classic 1950s science fiction movies such as The Day The World Stood Still and The Thing (From Another World).
Grantophone thus produces sounds similar to those you get if you partially fill a glass bottle with water and blow across its mouth. It can also produce much breathier sounds by adjusting the levels of vibrato, noise and reverb that are applied. (See also: Windows 8: the complete guide.)
The instrument conforms to the notes on a conventional scale and covers four octaves. You can switch on and off phonic effects, and use staccato and sinuous waveforms. The results sound variously industrial and otherworldly.
Although the app works on a regular Windows 8 laptop, you really need a device that supports multi-touch input in order to appreciate the app's phonic capabilities. By pressing several buttons at once and adjusting the volume or strength of an effect, a range of interesting effects can be achieved. Even on a non-touchscreen laptop keyboard, the instrument is quite diverting, but it's with complex sounds that it comes alive.
Unfortunately, it seems rather hit-and-miss whether you end up being able to reproduce combinations of sounds that work well together. There's no record option on the desktop version, though there is on the Windows Phone version, and no native save option. You'll need to remember the key combinations you chose on Grantophone's grid if you want to use this app for composition rather than simply freeform experimentation.