The Nubian Arch/Vault
A similar promise symbolized by the Nubian Arch/vault, an inverted catenary curve, occurred in ancient Africa 6,000 years ago.
Structural reciprocity in Egyptian society was the moral code governing social interactions and exchange. In the long run, it developed trust, affection, and cooperation, which created social capital, allowing individuals, families, and groups access to more extensive social networks.
The Nubian arch/vault, predicated on the structural reciprocity of its mud bricks, produced spaces and forms expressing its social determinate.
These spaces and forms acted as guided imagery and gestalt, symbolizing the spatial representation of the community's wealth of ethical behavior and commercial success to others.