[singularity2001]

At least for the Eurasian civilizations, the term 'independently invented' is easily falsified:

Metallurgy and chariots arrived in China from the west; Mesopotamia, Indus and Egypt were in very close contact. So much so, that the cultural artifacts of the epochs preceding the first dynasties are near identical (including building plans!) : https://raw.githubusercontent.com/wiki/pannous/hieros/susa-e...