+This positioning of the tie is better, but maybe it should be raised
+more in the center. The following example does this, this time using
+the alternative @code{\tweak} form:
+
+@lilypond[verbatim,quote,relative=1]
+<<
+ {
+ e1-\shape #'((0 . 0.5) (0 . 1) (0 . 1) (0 . 0.5)) ~ e
+ }
+\\
+ { r4 <g c,> <g c,> <g c,> }
+>>
+@end lilypond
+
+Changes to the horizontal positions of the control points may be made
+in the same way, and two different curves starting at the same
+musical moment may also be shaped:
+
+@lilypond[verbatim,quote,ragged-right,relative=2]
+c8(\( a) a'4 e c\)
+\shape #'((0.7 . -0.4) (0.5 . -0.4) (0.3 . -0.3) (0 . -0.2)) Slur
+\shape #'((0 . 0) (0 . 0.5) (0 . 0.5) (0 . 0)) PhrasingSlur
+c8(\( a) a'4 e c\)
+@end lilypond
+
+The @code{\shape} function can also displace the control points of
+curves which stretch across line breaks. Each piece of the broken
+curve can be given its own list of offsets. If changes to a
+particular segment are not needed, the empty list can serve as a
+placeholder. In this example the line break makes the single slur
+look like two:
+
+@lilypond[verbatim,quote,ragged-right,relative=1]
+c4( f g c
+\break
+d,4 c' f, c)
+@end lilypond
+
+Changing the shapes of the two halves of the slur makes it clearer
+that the slur continues over the line break:
+
+@lilypond[verbatim,quote,ragged-right,relative=1]
+% () may be used as a shorthand for ((0 . 0) (0 . 0) (0 . 0) (0 . 0))
+% if any of the segments does not need to be changed
+\shape #'(
+ (( 0 . 0) (0 . 0) (0 . 0) (0 . 1))
+ ((0.5 . 1.5) (1 . 0) (0 . 0) (0 . -1.5))
+ ) Slur
+c4( f g c
+\break
+d,4 c' f, c)
+@end lilypond
+
+If an S-shaped curve is required the control points must always be
+adjusted manually --- LilyPond will never select such shapes
+automatically.
+
+@lilypond[verbatim,quote,relative=2]
+c8( e b-> f d' a e-> g)
+\shape #'((0 . -1) (5.5 . -0.5) (-5.5 . -10.5) (0 . -5.5)) PhrasingSlur
+c8\( e b-> f d' a e-> g\)
+@end lilypond
+
+@subsubsubheading Specifying control points explicitly
+
+The coordinates of the Bézier control points are specified in units
+of staff-spaces. The X@tie{}coordinate is relative to the reference
+point of the note to which the tie or slur is attached, and the
+Y@tie{}coordinate is relative to the staff center line. The
+coordinates are specified as a list of four pairs of decimal numbers
+(reals). One approach is to estimate the coordinates of the two
+end points, and then guess the two intermediate points. The optimum
+values are then found by trial and error. Be aware that these values
+may need to be manually adjusted if any further changes are made to
+the music or the layout.
+
+One situation where specifying the control points explicitly is
+preferable to specifying displacements is when they need to be
+specified relative to a single note. Here is an example of this.
+It shows one way of indicating a slur extending into alternative
+sections of a volta repeat.
+
+@lilypond[verbatim,quote,relative=2]
+c1
+\repeat volta 3 { c4 d( e f }
+\alternative {
+ { g2) d }
+ {
+ g2
+ % create a slur and move it to a new position
+ % the <> is just an empty chord to carry the slur termination
+ -\tweak control-points #'((-2 . 3.8) (-1 . 3.9) (0 . 4) (1 . 3.4)) ( <> )
+ f,
+ }
+ {
+ e'2
+ % create a slur and move it to a new position
+ -\tweak control-points #'((-2 . 3) (-1 . 3.1) (0 . 3.2) (1 . 2.4)) ( <> )
+ f,
+ }
+}
+@end lilypond
+