Found a tweet to a nice vdeo by Levi NIha. Inspired by it I developed his code to produce a more extensive backing track, and then thought what it needs is an instrument providing a tune on top, so I played my small polyphonicsynth in a separate Sonic Pi buffer and played along with my midi keyboard, recording the resultant audio in Sonic Pi. If you listen carefully you will here to small audio cues to me to prepare ending the midi input to coincide with the end of the track. The description in SonidCloud alos give a link to Levi’s video.