The court may require that the verdict consist wholly of special written findings on each issue of fact. It shall then submit in writing questions susceptible of categorical or brief answers, or forms of several special findings that the jury might properly make under the issues and evidence, or submit the issues and require the findings in any other appropriate manner. It shall so instruct the jury as to enable it to find upon each issue submitted. If the submission omits any issue of fact, any party not demanding submission of such issue before the jury retires waives jury trial thereof, and the court may find upon it; failing which, it shall be deemed found in accord with the judgment on the special verdict. The court shall direct such judgment on the special verdict and answers as is appropriate thereto. Special interrogatories under Iowa Code chapter 668 shall be treated as special verdicts for purposes of the rules in this chapter.