+@cindex stretchability of staves
+@cindex staves, stretchability
+
+The above layout of the organ staves is almost perfect; however,
+there is a slight defect which is not visible by looking at just a
+single system: The distance of the pedal staff to the left hand staff
+should behave approximately the same as the right hand staff to the
+left hand staff. In particular, the stretchability of staves in a
+@code{PianoStaff} context is limited (so that the distance between
+the staves for the left and right hand can't become too large), and
+the pedal staff should behave similarly.
+
+@cindex sub-properties
+@cindex properties, sub-properties
+@cindex graphical objects
+@cindex objects, graphical
+@cindex grobs
+
+Stretchability of staves can be controlled with the
+@code{staff-staff-spacing} property of the
+@code{VerticalAxisGroup} @q{graphical object} (commonly called
+@q{grob}s within the lilypond documentation) -- don't worry about
+the details right now; this is fully explained later. For the
+curious, have a look at @ruser{Overview of modifying properties}.
+In this case, we want to modify the @code{stretchability}
+sub-property only. Again, for the curious, you can find the
+default values for the staff-staff-spacing property
+in file @file{scm/define-grobs.scm} by looking up the definition
+of the @code{VerticalAxisGroup} grob. The value for
+@code{stretchability} is taken from the definition of the
+@code{PianoStaff} context (in file @file{ly/engraver-init.ly})
+so that the values are identical.
+
+@example
+\score @{
+ << % PianoStaff and Pedal Staff must be simultaneous
+ \new PianoStaff <<
+ \new Staff = "ManualOne" <<
+ \keyTime % set key and time signature
+ \clef "treble"
+ \new Voice @{
+ \voiceOne
+ \ManualOneVoiceOneMusic
+ @}
+ \new Voice @{
+ \voiceTwo
+ \ManualOneVoiceTwoMusic
+ @}
+ >> % end ManualOne Staff context
+ \new Staff = "ManualTwo" \with @{
+ \override VerticalAxisGroup
+ #'staff-staff-spacing #'stretchability = 5
+ @} <<
+ \keyTime
+ \clef "bass"
+ \new Voice @{
+ \ManualTwoMusic
+ @}
+ >> % end ManualTwo Staff context
+ >> % end PianoStaff context
+ \new Staff = "PedalOrgan" <<
+ \keyTime
+ \clef "bass"
+ \new Voice @{
+ \PedalOrganMusic
+ @}
+ >> % end PedalOrgan Staff
+ >>
+@} % end Score context
+@end example