6 Test clef engraver by setting \property directly. \clef is merely a front-end to this.
11 \property Staff.clefGlyph = #"clefs-F"
12 \property Staff.clefPosition = #2
14 \property Staff.clefGlyph = #"clefs-G"
16 \property Staff.clefGlyph = #"clefs-C"
19 \property Staff.clefOctavation = #7
21 \property Staff.clefOctavation = #0
22 \property Staff.clefPosition = #0