A primary problem in drawing and painting is solved in the division of space. Over the centuries artists have solved this problem in their own way and therein lies the reason Art is such a tremendous and important part of the human experience. The way the artist solves the problem gives us an insight into their thinking and the thinking of all mankind.
Threes come up often in the visual arts and Thomas Moran (1837-1926) solved the problem of division of space in an extraordinary way. He used the triad of 3 color temperatures: cool, neutral, and warm.