\version "2.19.25"
#(set-global-staff-size 40)

\score {
  \new PianoStaff \with { \consists #Span_stem_engraver }
  <<
    \new Staff
    <<
      \repeat tremolo 4 {
        a'16 bes'16
      }
      \\
      {
        \voiceFour \crossStaff {
          \once\override Stem.length = 12
          <g' e'>4.
        }
      }
    >>
    \new Staff
    <<
      \clef bass
      { \voiceFour \tweak NoteColumn.force-hshift 0.995 cis'4. }
      \\
      { \voiceTwo a,2 }
    >>
  >>
}