10 Noteheads for improvisation have a different shape.
16 improOn = \notes {\change Voice = impro }
17 improOff = \notes {\change SquashVoice = melo }
19 global = \notes { s1*3 \bar "|." }
23 \context ChordNames \chords {e8*7:m7 a2.:m7 bes4:m7 b1:m7 e8:m }
24 \context Staff \notes <<
25 \context SquashVoice = impro { \global }
26 \context Voice = melo \transpose c c' {
27 e8 e g a a16(bes)(a8) g \improOn e8
29 ~fis2 \improOff a16(bes) a8 g e
38 \consists Pitch_squash_engraver
40 NoteHead \override #'style = #'slash
50 \remove "Accidental_engraver"