LilyPond cross-staff stems

Cross-staff stem lengths set manually.

   \layout {
      ragged-right = ##t
      \context {
         \Score
         proportionalNotationDuration = #(ly:make-moment 1 48)
         \override NonMusicalPaperColumn
         #'line-break-system-details =
         #'((alignment-offsets . (0 -8)))
         autoBeaming = ##f } }

   \new PianoStaff <<
      \new Staff = "RH" {
         #(set-accidental-style 'forget)
         \override Beam #'positions = #'(8 . 8)
         \override Stem #'direction = #up
         <d'>16 [
         <d'>16
         <d'>16
         <d'>16 ]
      }
      \new Staff = "LH" {
         \clef bass
         \override Stem #'flag-style = #'no-flag
         \override Stem #'length = #20
         \override Stem #'cross-staff = ##t
         <c>16
         <c>16
         <c>16
         <c>16
      }
   >>

Stem overrides to 'flag-style, 'length and 'cross-staff all matter.