Some kind of hierarchy - but nested abstractions seem difficult to name and unhelpful to use. What about picking a single instance (actual song) as representat

Some kind of hierarchy - but nested abstractions seem difficult to name and unhelpful to use. What about picking a single instance (actual song) as representative? A platonic form, at that level of abstraction. Expanding that node would give "more like this" - consisting also of actual instances, representative of further sets.