Substitute prolongation

The mechanic

A hamza comes first and the madd letter follows it, the reverse of the connected and separated cases. The mushaf prints no madd sign here.

Where it occurs

Its condition

ء ا و ي

Length, as reported

Two harakat is what is reported in Hafs; other qira'at report three options. Stating 'two' without qualification silently asserts one qira'a.

A place in the text

إِلَّا ٱلَّذِينَ ءَامَنُواْ وَعَمِلُواْ ٱلصَّٰلِحَٰتِ وَتَوَاصَوۡاْ بِٱلۡحَقِّ وَتَوَاصَوۡاْ بِٱلصَّبۡرِ

The marked spot was located in this ayah's own text at build time — Al-Asr 103:3.