\version "2.19.17"
#(ly:set-option 'point-and-click #f)
\paper { #(set-paper-size "a8" 'landscape) }
\header { tagline = ##f }

long-accent-markup = \markup { \scale #'(2 . 1)
                               \musicglyph #"scripts.sforzato" }
long-accent-stil =
#(lambda (grob)
   (grob-interpret-markup grob long-accent-markup))
acc = -\tweak stencil #long-accent-stil \tweak self-alignment-X -1 ->
accD = -\tweak self-alignment-X -1 \tweak parent-alignment-X -1
#(make-dynamic-script long-accent-markup)

{
  \dynamicUp

  c''2-> c''\acc << c'' { s4\> s\! } >>
  c''2-> c''\accD << c'' { s4\> s\! } >>
}