% piece.ly
% (This is the global definitions file)

global= {
  \time 4/4
  \key c \major
}

Violinone = \new Voice \relative c'' {
  c2 d e1
  \bar "|."
}

Violintwo = \new Voice \relative c'' {
  g2 g e1
  \bar "|."
}

Viola = \new Voice \relative c' {
  \clef alto
  e2 d c1
  \bar "|."
}

Cello = \new Voice \relative c' {
  \clef bass
  c2 b a1
  \bar "|."
}

music = {
  <<
    \tag #'score \tag #'vn1
    \new Staff \with { instrumentName = "Violin 1" }
    << \global \Violinone >>

    \tag #'score \tag #'vn2
    \new Staff \with { instrumentName = "Violin 2" }
    << \global \Violintwo >>

    \tag #'score \tag #'vla
    \new Staff \with { instrumentName = "Viola" }
    << \global \Viola >>

    \tag #'score \tag #'vlc
    \new Staff \with { instrumentName = "Cello" }
    << \global \Cello >>
  >>
}

% These are the other files you need to save on your computer

% score.ly
% (This is the main file)

% uncomment the line below when using a separate file
%\include "piece.ly"

#(set-global-staff-size 14)

\score {
  \new StaffGroup \keepWithTag #'score \music
  \layout { }
  \midi { }
}


%{ Uncomment this block when using separate files

% vn1.ly
% (This is the Violin 1 part file)

\include "piece.ly"
\score {
  \keepWithTag #'vn1 \music
  \layout { }
}

% vn2.ly
% (This is the Violin 2 part file)

\include "piece.ly"
\score {
  \keepWithTag #'vn2 \music
  \layout { }
}

% vla.ly
% (This is the Viola part file)

\include "piece.ly"
\score {
  \keepWithTag #'vla \music
  \layout { }
}

% vlc.ly
% (This is the Cello part file)

\include "piece.ly"
\score {
  \keepWithTag #'vlc \music
  \layout { }
}

%}