5 Test clef engraver by setting \property directly. \clef is merely a front-end to this.
10 \property Staff.clefGlyph = #"clefs-F"
11 \property Staff.clefPosition = #2
13 \property Staff.clefGlyph = #"clefs-G"
15 \property Staff.clefGlyph = #"clefs-C"
18 \property Staff.clefOctavation = #7
20 \property Staff.clefOctavation = #0
21 \property Staff.clefPosition = #0