Vertical and horizontal lines are the expression of two opposing forces; they exist everywhere and dominate everything; their reciprocal action const… - Piet Mondrian

In 'De Nieuwe beelding in de Schilderkunst', Piet Mondriaan, 'De Stijl' No. 1, October 1917, p. 54

With that work [Mondrian is referring to his figurative painting 'Devotion' he painted in 1908, of a devotedly looking girl] I only envisaged a girl conceived devotedly.. ..and by giving the hair that sort of red, to tone down the material side of things, to suppress any thoughts about 'hair', 'costume', etc, and to stress the spiritual. I believe that color and line can do much towards this end; moreover, I should not wish to do without line.. .It is precisely the overall line of a thing which I find fundamentally important, and also, the colour.

That is what we are against [the ancient-Greek ideas about art], because that is the key to the classic and tragic finality from which we must free ourselves.