thepaper = \paper {
  indent = 0
  tagline = ##f
}
columns = #3
#(define getlinewidth
   (lambda (paper)
     (let* (
             (landscape (ly:output-def-lookup paper 'landscape))
             (output-scale (ly:output-def-lookup paper 'output-scale))
             (paper-width (ly:output-def-lookup paper 'paper-width))
             (paper-height (ly:output-def-lookup paper 'paper-height))
             (indent (ly:output-def-lookup paper 'indent))
             (plain-line-width (ly:output-def-lookup paper 'line-width))
             (plain-left-margin (ly:output-def-lookup paper 'left-margin))
             (w (if landscape paper-height paper-width))
             (left-margin (if (null? plain-left-margin)
                              (if (null? plain-line-width)
                                  10
                                  (/ (- w plain-line-width) 2))
                              plain-left-margin))
             (line-width (if (null? plain-line-width)
                             (- w (* (* columns 2) left-margin))
                             plain-line-width)))
       (/ line-width columns)
       )))
\paper {
  \thepaper
}
\markup \fill-line {
  \column {
    \score {
      \relative c' {
        \repeat unfold 8 {c4 d e f g1}
      }
      \layout {
        line-width = #(getlinewidth thepaper)
      }
    }
  }
  \column {
    \score {
      \relative c'' {
        \repeat unfold 8 {g4 f e d c1}
      }
      \layout {
        line-width = #(getlinewidth thepaper)
      }
    }
  }
  \column {
    \score {
      \relative c' {
        \repeat unfold 8 {c4 d e f g1}
      }
      \layout {
        line-width = #(getlinewidth thepaper)
      }
    }
  }
}