(not for school question)
Theoretically, if I wrote every possible combination for a 4 note melody and chord progression, and then I went to write a new song with an 8 note melody, wouldn't I just be reusing two 4 note melodies I already used. And so forth, if I wrote a 16 note melody, would that just be four of the 4 note melodies already used, if all had been used up? And same question for chord progressions. Does this make the amount of piano pieces possible finite?