code: function(vec){
  			var cx = this.y * vec.z - vec.y * this.z;
  			var cy = this.z * vec.x - vec.z * this.x;
  			this.z = this.x * vec.y - vec.x * this.y;
  			this.y = cy;
  			this.x = cx;
  			return this;
  		}
docs: Calculates cross-product with vector v. The resulting vector is
  perpendicular to both the current and supplied vector and overrides the
  current.
  
  @param v
  the v
  
  @return itself