Why are boundaries in North Africa looks very geometric?

Question

Why are boundaries in North Africa looks very geometric?

Answer 1

Because the North Africa was carved up by colonial  countries, mainly Britain and France, to share out. Literally lines drawn on a map, becoming countries.

As simple as that.  

Answer 2

Because (for the most part) the nations there weren't formed around cultural or ethnic groups. The whole of North Africa was arbitrarily subdivided into nations by Britain, France and other colonial powers.

If you look at the Western US, it's much the same: states have geometrical boundaries, because the land was divided not by slow historical processes but by cartographers and legislators.