\version "2.24.4"
\header {
  title = "John Ryan's Polka (trop compliqué)"
}

lhA = {
  r8 <d d'>8 r8 <g g'>8
  r8 <d d'>8 r8 <d d'>8
}

leftHand = {
  \repeat volta 2 {
    \lhA \repeat volta 3 { \volta #'() { s1*0^\markup { \bold "2×" } } \lhA }
    r8 <d d'>8 r8 <a a'>8
    r8 <d d'>8 r8 <d d'>8
  }
}

rhA = \chordmode {
  d'/fis s d'/fis s 
  g s d'/fis s 
}

rightHand = \chordmode {
  \tempo 4 = 160
  \time 2/4
  \key d \major
  \repeat volta 2 {
    \alternative {
      \volta 1 { s4 d'8/fis s }
      \volta 2 { d'8/fis s d'/fis s }
    }
    g8 s d'/fis s 
    \repeat volta 2 { \rhA }
    d'/fis s d'/fis s 
    a/e s d'/fis s 
  }
}

piano = { 
  \tempo 4 = 160
  \time 2/4
  \key d \major
  \leftHand
}

\new Staff <<
  \new Voice = "right" { \voiceOne \rightHand }
  \new Voice= "left" { \voiceTwo \leftHand }
>>

% \score {
%   <<
%     \new ChordNames {
%       \set chordChanges = ##t
%       \rightHand
%     }
%     \new Staff \rightHand
%     \new Staff \piano
%   >>
%   \layout{ }
%   \midi { }
% }