AnglePatch:

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   Draw a patch showing the inner angle between two vectors.
   Enter a rotation axis if the angle may be more than 180 degrees.
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   Form:
   AnglePatch( v1, v2, z, c, f )
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   ------
   Inputs
   ------
   v1             (3,1)  First vector
   v2             (3,1)  Second vector
   z              (3,1)  Rotation axis, optional
   c              (:)    Color code, 'g', 'r', etc
   f              (1,1)  Saturation, between 0 and 1

   -------
   Outputs
   -------
   none

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Children:

Common: Math/Cross
Common: Math/Dot
Common: Math/Mag
Common: Math/Unit