Add an arrow to a label style to indicate direction.

Direction arrow properties
The standard AutoCAD arrowheads are used in Autodesk Civil 3D:
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 architectural tick  | 
 
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 datum triangle filled  | 
 
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 oblique  | 
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 box  | 
 
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 dot  | 
 
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 open  | 
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 box filled  | 
 
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 dot blank  | 
 
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 open 30  | 
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 closed blank  | 
 
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 dot small  | 
 
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 origin indicator  | 
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 closed filled  | 
 
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 dot small blank  | 
 
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 origin indicator 2  | 
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 datum triangle  | 
 
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 integral  | 
 
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 right angle  |