Is that where he got it?

Just to demonstrate the holes in my knowledge of the classical repertoire …

I didn’t realize Alfred Schnittke pretty much refashioned Ludwig Van Beethoven’s Grosse Fuge for his String Quartet No. 3.

As such, I can’t listen to the Grosse Fuge without my ears filling in all the clustered notes Schnittke "added". Even as a melody in its original form, it’s pretty dissonant.