In the work of François Morellet (1926-2016, France) lines and angles meet each other. He worked systematically: he drew up strict rules and even used mathematical formulas. He based the position of the red painted steel beams on the decimals of the number π, which indicates the ratio between the circumference and the diameter of a circle. The result is a rectangular interplay of lines, which seems spontaneous, but is in fact carefully composed. The horizontal and vertical black lines on the wall also, according to the title, engage in a ruthless confrontation.