Rule 1: 1. Form VII اِنْفَعَلَ: the passive-reflexive of Form I
Prefix اِنْـ to the Form I stem: كَسَرَ he broke (something) gives اِنْكَسَرَ it broke, got broken; قَطَعَ he cut gives اِنْقَطَعَ it was cut off, ceased; فَتَحَ gives اِنْفَتَحَ it opened; قَسَمَ gives اِنْقَسَمَ it was divided; صَرَفَ he sent away gives اِنْصَرَفَ he went away; قَلَبَ he turned (something) over gives اِنْقَلَبَ it overturned. Form VII is always intransitive: the object of Form I has become its subject. Imperfect يَنْكَسِرُ, verbal noun اِنْكِسَارٌ, participle مُنْكَسِرٌ.
اِنْكَسَرَ زُجَاجُ النَّافِذَةِ فِي الْحَافِلَةِ.
inkasara zujāju n-nāfidhati fi l-ḥāfilati
The window glass in the bus broke.
اِنْقَطَعَتِ الْكَهْرَبَاءُ عَنِ الْحَيِّ كُلِّهِ فِي اللَّيْلِ.
inqaṭaʿati l-kahrabāʾu ʿani l-ḥayyi kullihi fi l-layli
The electricity was cut off from the whole quarter during the night.
اِنْفَتَحَ بَابُ الْمَحَطَّةِ فَخَرَجَ النَّاسُ.
infataḥa bābu l-maḥaṭṭati fa-kharaja n-nāsu
The station door opened and the people came out.
يَنْصَرِفُ الْعُمَّالُ مِنَ الْمَصْنَعِ فِي السَّاعَةِ الْخَامِسَةِ.
yanṣarifu l-ʿummālu mina l-maṣnaʿi fi s-sāʿati l-khāmisati
The workers leave the factory at five o'clock.
اِنْقَسَمَ أَهْلُ الْحَيِّ إِلَى فَرِيقَيْنِ.
inqasama ahlu l-ḥayyi ilā farīqayni
The people of the quarter split into two parties.
Form I قَسَمَ 'to divide something'; Form VII 'to be divided, split'. Note that اِنْتَقَلَ 'to move house' is not Form VII but Form VIII: its ن is a radical.