Comment by ramses0

Have I got a thrill for you!

https://www.mutopiaproject.org

https://lilypond.org

https://www.hacklily.org

...it really helped me understand why "$SCORE = ( $MELODY + $BASS )" was sometimes superior to viewing sheet music as a "wall of notes and chords". You have to "play the wall" as it comes at you, but mentally, thinking of it as "melody goes la la la, bass goes boom bang boom" helps to provide context to what are the roles of the two notes you're playing.