\score{ 
	\context PianoStaff \notes < 
		\context Staff="up" <
			\clef treble
			\context Voice = one < \stemUp \tieUp \notes \transpose c'' \sequential {
				g4 bes2 a g c' bes a4
			}>
			
		>

		\context Staff="down" <
			\clef bass
			\context Voice = two < \notes \transpose c' \sequential {
				g2. f2 bes a8 g f2 g4 f
			}>
		>
	>

	\paper {
		\translator{
			\ThreadContext
			\remove "Note_heads_engraver"
			\consists "Completion_heads_engraver"
		}
	}
}