public Coordinate3D operator -( 
   Coordinate3D a,
   Coordinate3D b
)

// Easy 3D vectors
Coordinate3D v = new Coordinate3D(0, 1, 0);
// v.Magnitude = 1

Coordinate3D other = new Coordinate3D(-1, 0, 0);
// other.Magnitude = -1

double dotProduct = v.DotProduct(other);      // dotProduct = 0

Coordinate3D crossProduct = v.CrossProduct(other);
// crossProduct.X = 0
// crossProduct.Y = 0
// crossProduct.Z = 1

Coordinate3D addVector = v.AddCoordinate3D(other);
// addVector.X = -1
// addVector.Y = 1
// addVector.Z = 0

// Rotate around x-axis
Coordinate3D w = v;
w.Rotate(Math.PI, other);
// w.X = 0
// w.Y = -1
// w.Z = 0

w.Scale(0.5);
// w.X = 0
// w.Y = -0.5
// w.Z = 0

w.Scale(-4);
// w.X = 0
// ww.Y = 2
// w.Z = 0
// w.Magnitude = 2

w.Move(3, 2, 0);
// w.X = 3
// w.Y = 4
// w.Z = 0
// w.Magnitude = 5


Coordinate3D emptyVector = new Coordinate3D();
// emptyVector = (0, 0, 0)
emptyVector.SetEmpty();
// emptyVector = (Nan, Nan, Nan)

Coordinate3D c1 = new Coordinate3D(2, 3, 4);
Coordinate3D c2 = new Coordinate3D(9, -1, 3);

var result_add = c1 + c2;
// result_add = (11, 2, 7)
var result_sub = c1 - c2;
// result_sub = (-7, 4, 1)

var b = result_sub != result_add;
// b = true

result_add = emptyVector + c1;
// result_add = (Nan, Nan, Nan)

b = result_add == emptyVector;
// b = true