A free app for Android, by Basis Five.
The idea of the app is to help you compose your own songs. The way it works is that you write a melody, and then you can play it on the piano. There are different ways to play the melody. You can do it as a normal piano, or with different instruments, like a guitar or bass. It is also possible to mix the sound of two different instruments.
The best part of the app is that it is very simple to use. It is not like a music editor in which you have to import songs and mix them together. In the app, you just write your melody and play it on the piano. You can also add different instruments to it. It is also possible to add effects to the melody.