1.
Center: "Always make the tip of the pen move in the middle of the stroke", that is, when the brush is running on the paper, the tip of the pen is in the middle of the stroke. This method of moving the brush is called Center strokes. Diagram: Center forward writes horizontally and vertically:
2.
Wide forward: The center of the pen is on one side. The center of the brush is not on the center line of the stipple, but is off to one side. When using side strokes, the brush hair of the brush is pointed sideways to one side of the stroke, which can easily cause the strokes to be smooth on one side and hairy on the other.