What is "mashq"

Mashq is one of the oldest calligraphic forms of the Arabic script. At the time of the emergence of Islam, this type of writing was likely already in use in various parts of the Arabian Peninsula. It is first attested during the reign of caliph Umar, making it one of the earliest forms of Arabic script, along with Hijazi and Kufic. It was used in most texts produced during the first and second centuries after the Hijra.