«وَإِمَّا بِالإِيغَالِ»
Another form of expansion is īghāl.
«هُوَ خَتْمُ الْبَيْتِ بِمَا يُفِيدُ نُكْتَةً يَتِمُّ الْمَعْنَى بِدُونِهَا»
It is ending a poetic line with wording that contributes a rhetorical point although the basic sense is complete without it.
Such a closing does not simply lengthen the line. It overlays an already intelligible proposition with a new nuance. One must distinguish completion of the core statement from enhancement of its effect.