JS Bach was the master of the fugue, but they appear everywhere. The first movement of my string quartet uses the form…sorta. A fugue (for those who aren’t familiar) puts a simple melody in a single voice (the viola in this case — ’cause I used to play it!). That voice wanders off as a 2nd voice repeats the melody verbatim, and that idea is repeated. Eventually, all the voices have “wandered off,” but pieces of the original melody keep appearing. Listen here, and see if you can hear this!