/// <summary>
/// Vectors form a concave angle.
/// </summary>
/// <param name="line1"></param>
/// <param name="line2"></param>
/// <param name="tolerance">Tolerance by which a double is considered to be zero or equal.</param>
/// <returns></returns>
public static bool IsConcave(LineSegment line1, LineSegment line2, double tolerance = ZeroTolerance)
{
return(VectorLibrary.IsConcave(line1.ToVector(), line2.ToVector(), tolerance));
}