BoraInKorea

In Korea, in the old stone age, primitive men used rocks as their main tools. On the left is the pictures of different rocks that were used in the era.
The stones are called "Tanseokki" in Korean. It means that the rocks were shaped by crashing the rocks. You can see that unlike normal stones which are round, the stones take certain shape. They are all sharp so those "tanseokki" are used to cut down trees, skinning animals and attacking animals.

And the picture on the left shows where the primitives used to live. Some used to live in caves as well.