+@node Single-staff polyphony
+@unnumberedsubsubsec Single-staff polyphony
+
+To typeset parallel pieces of music that have the same rhythm, they
+can be combined into a single @code{Voice} context, thus forming
+chords. To achieve this, enclose them in a simultaneous music
+construction:
+
+@lilypond[quote,relative=2,verbatim]
+\new Voice <<
+ { e4 f8 d e16 f g8 d4 }
+ { c4 d8 b c16 d e8 b4 }
+>>
+@end lilypond
+
+This method leads to strange beamings and warnings if the pieces of
+music do not have the same rhythm. To typeset multiple, truly
+independent voices in a single staff, the @code{<<@{...@} \\
+@{...@}>>} construction is used, where the two (or more) voices are
+separated by double backslashes.
+
+@lilypond[quote,relative=3,verbatim]
+<<
+ { r8 r16 g e8. f16 g8[ c,] f e16 d }
+ \\
+ { d16 c d8~ d16 b c8~ c16 b c8~ c16 b8. }
+>>
+@end lilypond
+
+First and third voices get stems up, second and fourth voices get
+stems down, third and fourth voice noteheads are horizontally shifted,
+and rests move to avoid collisions.
+
+@lilypond[quote,relative=3,verbatim]
+<<
+ { r8 g g g g f16 es f8 d }
+ \\
+ { es,8 r es r d r d r }
+ \\
+ { d'8 s c s bes s a s }
+>>
+@end lilypond
+
+For these purposes, the @code{\voiceOne} ... @code{\voiceFour}
+commands can be used instead. Spacing rests are often used to avoid
+too many rests, as seen in the example avobe.
+
+@predefined
+
+@funindex \voiceOne
+@code{\voiceOne},
+@funindex \voiceTwo
+@code{\voiceTwo},
+@funindex \voiceThree
+@code{\voiceThree},
+@funindex \voiceFour
+@code{\voiceFour}.
+
+
+@seealso
+
+Learning Manual:
+@rlearning{Voices contain music}.
+
+Snippets:
+@rlsr{Simultaneous notes}.
+
+
+@node Voice styles
+@unnumberedsubsubsec Voice styles
+
+@cindex voice styles
+@cindex styles, voice
+@cindex coloring voices
+
+Voices may be given distinct colors and shapes, allowing them to be
+easily identified:
+
+@lilypond[quote,relative=2,verbatim]
+<<
+ { \voiceOneStyle d4 c2 b4 }
+ \\
+ { \voiceTwoStyle e,2 e }
+ \\
+ { \voiceThreeStyle b2. c4 }
+ \\
+ { \voiceFourStyle g'2 g }
+>>
+@end lilypond
+
+To revert the standard presentation, the @code{\voiceNeutralstyle}
+command is used.
+
+These styles are arbitrarily defined but can be changed. For example,
+the initial definition for @code{\voiceOneStyle} is as follows:
+
+@example
+voiceOneStyle = @{
+ \override NoteHead #'style = #'diamond
+ \override NoteHead #'color = #red
+ \override Stem #'color = #red
+ \override Beam #'color = #red
+@}
+@end example
+
+
+@predefined
+
+@funindex \voiceOneStyle
+@code{\voiceOneStyle},
+@funindex \voiceTwoStyle
+@code{\voiceTwoStyle},
+@funindex \voiceThreeStyle
+@code{\voiceThreeStyle},
+@funindex \voiceFourStyle
+@code{\voiceFourStyle},
+@funindex \voiceNeutralStyle
+@code{\voiceNeutralStyle}.
+
+@seealso
+
+Learning Manual:
+@rlearning{I'm hearing Voices},
+@rlearning{Other sources of information}.
+
+Snippets:
+@rlsr{Simultaneous notes}.
+