+@c file spacing-optical.
+@c need to include it here, because we want two images.
+@lilypond
+\paper {
+ raggedright = ##t
+ indent = #0.0
+}
+
+music = {
+ c'4 e''4 e'4 b'4 |
+ \stemDown
+ b'8[ e'' a' e'']
+ \stemNeutral
+ e'8[ e'8 e'8 e'8]
+}
+
+\score
+{
+ \music
+ \layout {
+ \context {
+ \Staff
+ \override NoteSpacing #'stem-spacing-correction = #0.6
+ }
+ }
+}
+@end lilypond
+
+@lilypond
+\paper {
+ raggedright = ##t
+ indent = #0.0
+}
+
+music = {
+ c'4 e''4 e'4 b'4 |
+ \stemDown
+ b'8[ e'' a' e'']
+ \stemNeutral
+ e'8[ e'8 e'8 e'8]
+}
+\score
+{
+ \music
+ \layout {
+ \context {
+ \Staff
+ \override NoteSpacing #'stem-spacing-correction = #0.0
+ \override NoteSpacing #'same-direction-correction = #0.0
+ \override StaffSpacing #'stem-spacing-correction = #0.0
+ }
+ }
+}
+@end lilypond