+@code{\voiceFourStyle},
+@funindex \voiceNeutralStyle
+@code{\voiceNeutralStyle}.
+
+@seealso
+
+Learning Manual:
+@rlearning{I'm hearing Voices},
+@rlearning{Other sources of information}.
+
+Snippets:
+@rlsr{Simultaneous notes}.
+
+
+@node Collision resolution
+@unnumberedsubsubsec Collision resolution
+
+@cindex merging notes
+@cindex note collisions
+@cindex collisions
+@funindex \shiftOn
+@funindex \shiftOnn
+@funindex \shiftOnnn
+@funindex \shiftOff
+@cindex shift rest, automatic
+
+Note heads with equal durations are automatically merged, while
+note heads with unequal durations are not merged. Rests opposite
+a stem are shifted vertically.
+
+@lilypond[quote,verbatim,relative=2]
+<<
+ {
+ c8 d e d c d c4
+ g'2 fis
+ } \\ {
+ c2 c8. b16 c4
+ e,2 r
+ } \\ {
+ \oneVoice
+ s1
+ e8 a b c d2
+ }
+>>
+@end lilypond
+
+Note heads with different note heads may be merged, with the
+exception of half-note heads and quarter-note heads:
+
+@lilypond[quote,verbatim,relative=2]
+<<
+ {
+ \mergeDifferentlyHeadedOn
+ c8 d e d c d c4
+ g'2 fis
+ } \\ {
+ c2 c8. b16 c4
+ e,2 r
+ } \\ {
+ \oneVoice
+ s1
+ e8 a b c d2
+ }
+>>
+@end lilypond
+
+Note heads with different dots may be merged:
+
+@lilypond[quote,relative=2,verbatim]
+<<
+ {
+ \mergeDifferentlyHeadedOn
+ \mergeDifferentlyDottedOn
+ c8 d e d c d c4
+ g'2 fis
+ } \\ {
+ c2 c8. b16 c4
+ e,2 r
+ } \\ {
+ \oneVoice
+ s1
+ e8 a b c d2
+ }
+>>
+@end lilypond
+
+@cindex shift note
+
+The collision on the second measure happens because
+@code{merge-differently-headed} cannot successfully complete the
+merge when three or more notes line up in the same column -- in
+fact, you will obtain a warning for this reason. To allow the
+merge to work properly, apply a @code{\shift} to the note that
+should not be merged. Here, @code{\shiftOn} is applied to move
+the top @code{g} out of the column, and
+@code{merge-differently-headed} works properly.
+
+@lilypond[quote,relative=2,verbatim]
+<<
+ {
+ \mergeDifferentlyHeadedOn
+ \mergeDifferentlyDottedOn
+ c8 d e d c d c4
+ \shiftOn
+ g'2 fis
+ } \\ {
+ c2 c8. b16 c4
+ e,2 r
+ } \\ {
+ \oneVoice
+ s1
+ e8 a b c d2
+ }
+
+>>
+@end lilypond
+
+The @code{\shiftOn}, @code{\shiftOnn}, and @code{\shiftOnnn}
+commands specify the degree to which chords of the current voice
+should be shifted. The outer voices (normally: voices one and
+two) have @code{\shiftOff}, while the inner voices (three and
+four) have @code{\shiftOn}. @code{\shiftOnn} and
+@code{\shiftOnnn} define further shift levels.
+
+Notes are only merged if they have opposing stem directions (i.e., in
+@code{Voice} 1 and 2).
+
+@cindex multiple voices
+@cindex polyphonic music
+@cindex shifting voices
+
+@predefined
+
+@funindex \mergeDifferentlyDottedOn
+@code{\mergeDifferentlyDottedOn},
+@funindex \mergeDifferentlyDottedOff
+@code{\mergeDifferentlyDottedOff},
+@funindex \mergeDifferentlyHeadedOn
+@code{\mergeDifferentlyHeadedOn},
+@funindex \mergeDifferentlyHeadedOff
+@code{\mergeDifferentlyHeadedOff}.