+
+@node Single-staff polyphony
+@unnumberedsubsubsec Single-staff polyphony
+
+@cindex single-staff polyphony
+@cindex polyphony, single-staff
+@cindex voice
+@cindex lyrics assigned to one voice
+
+@funindex \voiceOne
+@funindex voiceOne
+@funindex \voiceOne ... \voiceFour
+@funindex Voice
+@funindex \oneVoice
+@funindex oneVoice
+
+@strong{@i{Explicitly instantiating voices}}
+
+The basic structure needed to achieve multiple independent
+voices in a single staff is illustrated in the following example:
+
+@lilypond[quote,relative=3,verbatim]
+\new Staff <<
+ \new Voice = "first"
+ { \voiceOne r8 r16 g e8. f16 g8[ c,] f e16 d }
+ \new Voice= "second"
+ { \voiceTwo d16 c d8~ d16 b c8~ c16 b c8~ c16 b8. }
+>>
+@end lilypond
+
+Here, voices are instantiated explicitly and are given names. The
+@code{\voiceOne} ... @code{\voiceFour} commands set up the voices
+so that first and third voices get stems up, second and fourth
+voices get stems down, third and fourth voice note heads are
+horizontally shifted, and rests in the respective voices are
+automatically moved to avoid collisions. The @code{\oneVoice}
+command returns all the voice settings to the neutral default
+directions.
+
+@strong{@i{Temporary polyphonic passages}}
+
+A temporary polyphonic passage can be created with the following
+construct:
+
+@example
+<< @{ \voiceOne ... @}
+ \new Voice @{ \voiceTwo ... @}
+>> \oneVoice
+@end example
+
+Here, the first expression within a temporary polyphonic passage is
+placed into the @code{Voice} context which was in use immediately
+before the polyphonic passage, and that same @code{Voice} context
+continues after the temporary section. Other expressions within
+the angle brackets are assigned to distinct temporary voices.
+This allows lyrics to be assigned to one continuing voice before,
+during and after a polyphonic section:
+
+@lilypond[quote, verbatim, relative=2]
+<<
+ \new Voice = "melody" {
+ a4
+ <<
+ {
+ \voiceOne
+ g f
+ }
+ \new Voice {
+ \voiceTwo
+ d2
+ }
+ >>
+ \oneVoice
+ e4
+ }
+ \new Lyrics \lyricsto "melody" {
+ This is my song.
+ }
+>>
+@end lilypond
+
+Here, the @code{\voiceOne} and @code{\voiceTwo} commands are
+required to define the settings of each voice.
+
+@strong{@i{The double backslash construct}}
+
+The @code{<< @{...@} \\ @{...@} >>} construct, where the two (or
+more) expressions are separated by double backslashes, behaves
+differently to the similar construct without the double backslashes:
+@emph{all} the expressions within this contruct are assigned
+to new @code{Voice} contexts. These new @code{Voice} contexts
+are created implicitly and are given the fixed names @code{"1"},
+@code{"2"}, etc.
+
+The first example could be typeset as follows:
+
+@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
+
+This syntax can be used where it does not matter that temporary
+voices are created and then discarded. These implicitly created
+voices are given the settings equivalent to the effect of the
+@code{\voiceOne} ... @code{\voiceFour} commands, in the order in
+which they appear in the code.
+
+In the following example, the intermediate voice has stems up,
+therefore we enter it in the third place, so it becomes voice
+three, which has the stems up as desired. Spacer rests are
+used to avoid printing doubled rests.
+
+@lilypond[quote,relative=3,verbatim]
+<<
+ { r8 g g g g f16 ees f8 d }
+ \\
+ { ees,8 r ees r d r d r }
+ \\
+ { d'8 s c s bes s a s }
+>>
+@end lilypond
+
+In all but the simplest works it is advisable to create explicit
+@code{Voice} contexts as explained in @rlearning{Contexts and engravers} and
+@rlearning{Explicitly instantiating voices}.
+
+@strong{@i{Identical rhythms}}
+
+In the special case that we want to typeset parallel pieces of music
+that have the same rhythm, we can combine them into a single
+@code{Voice} context, thus forming chords. To achieve this, enclose
+them in a simple simultaneous music construct within an explicit voice:
+
+@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.
+
+@predefined
+
+@code{\voiceOne},
+@code{\voiceTwo},
+@code{\voiceThree},
+@code{\voiceFour},
+@code{\oneVoice}.
+
+@seealso
+
+Learning Manual:
+@rlearning{Voices contain music},
+@rlearning{Explicitly instantiating voices}.
+
+Notation Reference:
+@ref{Percussion staves},
+@ref{Invisible rests}.
+
+Snippets:
+@rlsr{Simultaneous notes}.
+
+
+@node Voice styles
+@unnumberedsubsubsec Voice styles
+
+@cindex voice styles
+@cindex styles, voice
+@cindex coloring voices
+@funindex \voiceOneStyle
+@funindex \voiceTwoStyle
+@funindex \voiceThreeStyle
+@funindex \voiceFourStyle
+@funindex \voiceNeutralStyle
+
+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
+
+The @code{\voiceNeutralstyle} command is used to revert to the
+standard presentation.
+
+@predefined
+
+
+@code{\voiceOneStyle},
+
+@code{\voiceTwoStyle},
+@code{\voiceThreeStyle},
+@code{\voiceFourStyle},
+@code{\voiceNeutralStyle}.
+
+@seealso
+
+Learning Manual:
+@rlearning{I'm hearing Voices},
+@rlearning{Other sources of information}.
+
+Snippets:
+@rlsr{Simultaneous notes}.
+
+