code: function() {
              	var V = this.dup();
              	switch (V.elements.length) {
              	case 3: break;
              	case 2: V.elements.push(0); break;
              	default: return null;
              	}
              	return V;
                  }
docs: Utility to make sure vectors are 3D. If they are 2D, a zero z-component is added