\version "2.12.0"

rightTearWidth = #1
rightTearFixedLengths = #'(0 1 3 4 2)

rightTearGeneric =
  #(define-music-function (parser location lengths) (list?)
  #{
    #(define (x-ext n)
             (cons (* (list-ref $lengths n) (/ rightTearWidth 4)) rightTearWidth))
    #(define y-ext '(1.5 . 2.5))

    \once \override Staff.BarLine #'stencil = #ly:text-interface::print
    \once \override Staff.BarLine #'text = \markup
      \override #'(baseline-skip . 0) \with-color #white
      \column {
        \filled-box #(x-ext 0) #y-ext #0
        \filled-box #(x-ext 1) #y-ext #0
        \filled-box #(x-ext 2) #y-ext #0
        \filled-box #(x-ext 3) #y-ext #0
        \filled-box #(x-ext 4) #y-ext #0
      }
    \once \override Staff.BarLine #'X-extent = #(cons 0 (- rightTearWidth 0.1))
    \break
  #} )

rightTearFixed =
  #(define-music-function (parser location) ()
  #{ \rightTearGeneric \rightTearFixedLengths #} )

rightTearCustom =
  #(define-music-function (parser location lengths) (list?)
  #{ \rightTearGeneric #$lengths #} )

rightTearRandom =
  #(define-music-function (parser location) ()
  #{ \rightTearGeneric
    #(list (random 5) (random 5) (random 5) (random 5) (random 5)) #} )



\score {
  \relative {
    g'4 d' b d \rightTearRandom
    g,4 d' b d \rightTearFixed
    g,4 d' b d \rightTearFixed
    g,4 d' b d \rightTearFixed
    g,4 d' b d \rightTearFixed
  }
  \layout {
    indent = #0
    ragged-right = ##t
  }
}