The textbook gives a three-slot nominal paradigm based on number:
Word / formMeaning / explanation
مَفْعَلٌsingular: one place or time.
مَفْعَلَانِdual: two places or times.
مَفَاعِلُbroken plural: several places or times.
This is not the 14-person verbal paradigm. It is a nominal pattern showing changes in number.