Let's start with an artistic definition of a line. My favourite is from the "Master of Line over Colour" Paul Klee, a Swiss artist of German nationality, who said that "A line is a dot that went for a walk".

Line is a form with length and width but no depth. Usually a line represents an edge. It can be used as a contour, divider or decoration. A direction of a line can communicate mood. Horizontal lines convey calmness, vertical lines indicate a potential of a movement and diagonal lines strongly suggest movement as well as add the vitality to the picture.

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