Answer:
The manipulation occurs though the technique.
Explanation:
Different lines and shapes can give the viewer different moods/feelings/sensations. For example, if the artist uses short and quick strokes, a feeling of fear and anxiety might be perceived. On the contrary, soft and light lines can radiate a sensation of calmness.
In other words, the technique that the artist decides to use to draw certain lines and shapes will influence the emotional perception that the viewer will get.
