Diagrams.TwoD.Arrowheads
tri
dart
spike
thorn
lineHead
noHead
arrowheadTriangle
arrowheadDart
arrowheadSpike
arrowheadThorn
tri'
dart'
spike'
thorn'
lineTail
noTail
quill
block
arrowtailQuill
arrowtailBlock
type ArrowHT