Simple sequential composition scenario (ala Dec 2017)

export a number of "piano roll" fragments from Numbers into Notes
start nin-remixer with a (possibly empty) collection of fragments available (selected?) [as a working set?]
play some of the fragments
select an initial fragment to start the composition
system offers potential next fragments based on "compatible" key
play some of the offered fragments
sleect a fragment to come next in the composition
repeat and rinse
play entire composition
export resulting composition as "DMO" (maybe as link, or maybe as data)

Simple (expanded) composition scenario

export a number of "piano roll" fragments from Numbers into Notes
- (Push from NiN, or pull everything from NiN into another interface, or something else - unspecified as yet)
start nin-remixer with a (possibly empty) collection of fragments available (selected?) [as a working set?]
play some of the working set fragments
select an initial fragment to be part of the composition; fragment is inserted into an open-ended timeline.
System places cursor following the inserted fragment
system offers compatible fragments to appear at the cursor
- e.g. based on "compatible" key
User may:
- listen to any of the offered fragments
- select one of the offered fragments to be inserted into the timeline
- select a different position in the timeline; the set of offered fragments is updated
- switch to NiN interface to create a new fragment, and subsequently add to working set
- remove a fragment from the composition
- play some or all of the entire composition so far
- change compability model for offered fragments
Repeat and rinse
export resulting composition as "DMO" (maybe as link, or maybe as data)