Practice Tapes: no tune at all, just an ear warmer I do
When I approach my instrument, I often do this. I used to do it with a tanpura machine (creates a drone that is used in Northern Indian classical music), but now I use the gong. It's not really a composition. I just start from a note and try to pre-hear notes and lines and build something. Tonight, it became a little counterpoint, then it took a turn to colors based up a half step from the drone, then combines the two... whatever. It's my ear training warm up to make sure I am hearing the pitches (or get an honest take on when I am NOT hearing the pitches) prior to playing.