Pretty much all of the lines in this paintings are curved/squiggly. The clouds are the exception. They look almost straight, yet, at the same time, not straight. The lines on the hill give it dimension and make it look real, rather than making one big blob as a hill, this added a kind of texture to it. In the water, the painter used very small strokes to replicate the ripples of the water. The mountains/hills in the background are also somewhat layered, making them look more realistic.