This might not be a true tremolo, but it is a shortcut for showing each note is played twice like the last measure.
!NoteWorthyComposerClip(2.751,Single)
|Clef|Type:Treble
|Key|Signature:F#,C#,G#,D#,A#|Tonic:B
|TimeSig|Signature:2/4
|Tempo|Tempo:36|Pos:7
|Note|Dur:8th,Tenuto|Pos:-6|Opts:Stem=Up,Beam=First
|Note|Dur:8th,Tenuto|Pos:-6|Opts:Stem=Up,Beam=End
|Note|Dur:8th|Pos:-9|Opts:Stem=Up,Beam=First
|Note|Dur:64th,Slur|Pos:n-8|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-7|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-6|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-5|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-4|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-3|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:-2|Opts:Stem=Up,Beam
|Note|Dur:64th,Slur|Pos:n-1|Opts:Stem=Up,Beam=End
|Bar
|Text|Text:"written"|Font:StaffItalic|Pos:10
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=First|Pos:0|Opts:Stem=Down,Beam=First
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet|Pos:1|Opts:Stem=Down,Beam
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=End|Pos:n2|Opts:Stem=Down,Beam=End
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=First|Pos:3|Opts:Stem=Down,Beam=First
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet|Pos:4|Opts:Stem=Down,Beam
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=End|Pos:n5|Opts:Stem=Down,Beam=End
|Bar
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=First|Pos:n6|Opts:Stem=Down,Beam=First
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet|Pos:7|Opts:Stem=Down,Beam
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=End|Pos:8|Opts:Stem=Down,Beam=End
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=First|Pos:#9|Opts:Stem=Down,Beam=First
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet|Pos:10|Opts:Stem=Down,Beam
|User|TremoloSingle.ms|Pos:-2|Beams:1
|Note|Dur:8th,Triplet=End|Pos:#10|Opts:Stem=Down,Beam=End
|Bar|Style:Double
|Text|Text:"played"|Font:StaffItalic|Pos:11
|Note|Dur:16th,Triplet=First|Pos:0|Opts:Stem=Down,Beam=First
|Note|Dur:16th,Triplet|Pos:0|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:1|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:1|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:n2|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet=End|Pos:2|Opts:Stem=Down,Beam=End
|Note|Dur:16th,Triplet=First|Pos:3|Opts:Stem=Down,Beam=First
|Note|Dur:16th,Triplet|Pos:3|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:4|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:4|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet|Pos:n5|Opts:Stem=Down,Beam
|Note|Dur:16th,Triplet=End|Pos:5|Opts:Stem=Down,Beam=End
!NoteWorthyComposerClip-End
TIA