Why did the partition of africa create artificial boundaries?

The partition of Africa (also called, with term less aseptic scramble for Africa, but better known in English as the scramble for Africa, translated into "the elbowing for Africa") was the proliferation of claims on the European African territories between 1880 and the beginning of World War I, the so-called period of the New imperialism.
In the second half of the nineteenth century it took place the transition from imperialism "informal" control through military influence and economic dominance, that of direct rule in the territory. It is in these years the birth of colonial states proper.
 

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