I'm not from Africa, but I agree with you, @samminator, which is a continent little valued in the West for its cultural contributions. That's why I think this series that you start with this post is very necessary and fair. I didn't know those two contributions that you communicate, in metallurgy and orthopedics. These and others are contributions of an ancestral wisdom, as you say, of simple and natural roots. I will pay attention to the following posts. Thank you for your information.