Answer:
balance; proportion
Explanation:
Balance with regards to art has to do with the use of artistic elements like line, color, texture and form to design works of art such that it brings visual stability. Balance and proportion are part of the principles of the organization of art design.
Proportion has to do with how two or more elements in a composition relate and compare with respect to size, color, degree, etc.
So, the artist that painted a piece of modern art using straight, perpendicular lines of color that create right angles in the upper left color focused mainly on balance and proportion.
