The infographic above summarizes the genealogy and history of several Middle Eastern and North African flags, and as we can see, several of these countries' flags have more than one thing in common.
First of all, their color schemes are generally the same which include red, green, black, and white. Secondly, some of the flags' elements include a crescent moon, stars, or both. The meaning behind these colors and elements have something to do with the nations' history and identity.
Some sources suggest that the four colors represented the different periods of Arab history: black for the Rashidun and Abbasid caliphates, white for the Umayyad dynasty, green for the Fatimids and Rashidun successors of the Prophet Mohammed and Islam, and red for the Hashemite dynasty.
On the other hand, another theory points to a 14th-century verse by Iraqi poet Safi al-Din al-Hilli which states that the white symbolizes their acts, black their battles, green their fields, and red their swords.
As for the star and the crescent, these were originally Turkish symbols, which had been used to represent Islam since the Ottoman Empire.
Of course, the Middle Eastern states are not the only ones having similar-looking designs on their flags, as Scandinavian countries all bore crosses on their flags, just in different color schemes; Central American countries also have similar patterns and colors on their flags; and countries in the Pacific, Australia and Oceania bear similar elements on their flags as well.
(Image credit: Aofen/Reddit)