public void Can_OperateOnItself()
{
var pt = Point3d.WorldOrigin;
var pt2 = new Point3d(1, 0, 0);
pt.Add(pt2);
Assert.True(pt == pt2);
pt.Substract(pt2);
Assert.True(pt == Point3d.WorldOrigin);
var pt3 = pt2 * 2;
pt2.Multiply(2);
Assert.True(pt2 == pt3);
pt2.Divide(2);
Assert.True(pt2 == new Point3d(1, 0, 0));
pt2.Negate();
Assert.True(pt2 == new Point3d(-1, 0, 0));
}