That's an odd-looking river. The riverbank is a nearly straight line with no slope, and just some larger stones put in a neat row along the edge, like a man-made rock garden.

NWSiaCB said:
That's an odd-looking river. The riverbank is a nearly straight line with no slope, and just some larger stones put in a neat row along the edge, like a man-made rock garden.

along the edge

Yukari is fooling around again.