Merging with nasalisation

The mechanic

Before ي ن م و at the start of the next word, the noon or tanween is folded into that letter — which takes a shadda — while the nasal sound is held. In the KFGQPC text the noon is written bare and the tanween marks are stacked.

Where it occurs

The four letters this idgham folds into

ي ن م و

A place in the text

فِي جِيدِهَا حَبۡلٞ مِّن مَّسَدِۭ

The marked spot was located in this ayah's own text at build time — Al-Masad 111:5.