4 Stem tremolos or rolls are tremolo signs that look like beam segments
5 crossing stems. If the stem is in a beam, the tremolo must be parallel
6 to the beam. If the stem is invisible (eg. on a whole note), the
7 tremolo must be centered on the note.
13 \context Voice
\notes \relative c''{
14 \property Voice
.Text
\set #'direction
= #1
15 \property Voice
.TextScript
\set #'padding
= #5
16 a1:4^":4" a:8^":8" c:16^":16" a:32^":32" a^"x" a:^":"
17 a4:4 c:8 a:16 c:32 a a: a2:
26 c,16:32 c: c c a16:32 a: a a