Displaying complex chords
Here is a way to display a chord where the same note is played twice
with different accidentals.
fixA = {
\once \override Stem.length = #11
}
fixB = {
\once \override NoteHead.X-offset = #1.7
\once \override Stem.length = #7
\once \override Stem.rotation = #'(45 0 0)
\once \override Stem.extra-offset = #'(-0.1 . -0.2)
\once \override Flag.style = #'no-flag
\once \override Accidental.extra-offset = #'(4 . -.1)
}
\relative c' {
<< { \fixA <b d!>8 } \\ { \voiceThree \fixB dis } >> s
}