During the 1920s Kandinsky produced a lot of paintings using initial watercolours before adding detail with ink and pen over the top. He merged the blurred nature of his painted backgrounds with the geometric style of his drawing skills. The end result somehow worked. We can see this on many occasions during 1929 which was the year of this particular artwork.
Only the most skilled of draughtsman would be able to draw directly on a canvas or completed watercolour without fear of ruining all of the previous work. Kandinsky was just the person who understood geometry as well as drawing and was confident in this process of producing art, indeed he used it frequently.
This painting features several grids, some curved lines running in parallel that gives the impression of a path leading up to an abstract form of a house. There are then other series of multiple lines running in parallel that slowly get closer and closer to each other, giving the impression of a landscape scene. When considering the title of Varied Rectangles, it feels much like an experiment by Kandinsky into his different geometric ideas, spreading the canvas with watercolour and precise strokes of indian ink.