\version "2.19.36"
   
%% c/p from lily-library.scm because it's not public
#(define (sign x)
  (if (= x 0)
      0
      (if (< x 0) -1 1)))
      
foo =
\override Beam.stencil =
  #(lambda (grob)
    (let* ((stil (ly:beam::print grob))
           (beam-y-pos (ly:grob-property grob 'positions))
           (beam-x-pos (ly:grob-property grob 'X-positions))
           (stems (ly:grob-object grob 'stems))
           (first-stem (ly:grob-array-ref stems 0))
           (first-stem-length (ly:grob-property  first-stem 'length))
           (delta-beam-y-pos (- (cdr beam-y-pos) (car beam-y-pos)))
           (delta-beam-x-pos (- (cdr beam-x-pos) (car beam-x-pos)))
           (beam-height
             (lambda (n) (* (/ delta-beam-y-pos delta-beam-x-pos) n)))
           (beam-dir (ly:grob-property grob 'direction))
           (slant (sign (- (cdr beam-y-pos) (car beam-y-pos))))
           (thick 0.1)
           (duration (ly:grob-property (ly:grob-parent grob X) 'duration-log))
           (beam-count (- duration 2))
           (beam-thickness (ly:grob-property grob 'beam-thickness))
           (space-between-beams (* 0.46 (ly:grob-property grob 'gap 0.8))) 
           (orig-beam-length-at-stem 
             (+ (* beam-count beam-thickness)
           	(* (- beam-count 1) space-between-beams)))
           (padding-corr
             (min
               (max (+ 1 orig-beam-length-at-stem) 1.5)
               (* 0.5 (- first-stem-length orig-beam-length-at-stem))))
           (x-start -0.4)
           (y-start 0)
           (x-end 1.5)
           (y-end 
             (* beam-dir 
                (+ 
                   padding-corr
                   0.5  
                   (* beam-dir (beam-height 1.5)))))
           (slash 
             (make-line-stencil 
               thick 
               x-start  ;; start x
               y-start  ;; start y
               x-end    ;; stop x
               y-end    ;; stop y
               )))
    (ly:stencil-combine-at-edge
      stil
      Y
      beam-dir
      slash
      (-
         ;; set slash really at edge of beam:
         (if (or (and (>= slant 0) (> beam-dir 0))
                 (and (< slant 0) (< beam-dir 0)))
             (* delta-beam-y-pos (- beam-dir))
             0)
         ;; add sufficient padding
         padding-corr))))
    
startAcciaccaturaMusic =  {
    <>\startGraceSlur
    \temporary \override Flag.stroke-style = #"grace"
    \temporary \foo
}

stopAcciaccaturaMusic =  {
    \revert Beam.stencil
    \revert Flag.stroke-style
    <>\stopGraceSlur
}
 
 \new Staff {
   \relative c' {
     \acciaccatura { d16 e f g } d4
     \acciaccatura { d'16 c b a } d4
     \acciaccatura { g16 a b c } d4
     \acciaccatura { g16 a b c } d4
     \clef bass      
     \acciaccatura { d,,,16 c b a  } g4
     \acciaccatura { d16 c b a } g4
     \acciaccatura { d16 c b a } g4
     \acciaccatura { d16 c b a } g4
     \acciaccatura { d'16 d d d } g4
   }
 }

\new Staff {
  \relative c' {
    \stemDown
    \acciaccatura { \stemDown d16 e f g } d4
    \acciaccatura { \stemDown d'16 c b a } d4
    \acciaccatura { \stemDown g16 a b c } d4
    \acciaccatura { \stemDown g16 a b c } d4
    \clef bass
    \acciaccatura { \stemDown d,,,16 c b a  } g4
    \acciaccatura { \stemDown d16 c b a } g4
    \acciaccatura { \stemDown d16 c b a } g4
    \acciaccatura { \stemDown d16 c b a } g4
    \acciaccatura { \stemDown d'16 d d d } g4
  }
}


\new Staff {
  \relative c'' {
    \acciaccatura {
      dis32[ e, a' bes, cis, d' ]
    }
    es,4
  }
}


\new PianoStaff <<
  \new Staff = "1" {
    s1*0
    \grace {
      \foo
      \stemDown
      a'''16[
      \change Staff = "2"
      \stemUp
      bes,
      \change Staff = "1"
      \stemDown
      fis''16
      \change Staff = "2"
      \stemUp
      g]
    }
    \change Staff = "1"
    es'4
  }
  \new Staff = "2" {
    \clef bass
    \grace s4
    s4
  }
>>