Some people think that square forms connect to objective thinking, while round forms not. But that is not so. Those impressions come mainly from social style. One following rules is like following some line or square forms, while a successfull skilled person typically has round satisfied forms. These are two different skil levels. Round is difficult also if you mix it with some food, especially if the food isn't especially well made. Well made food refers to skills in a way and can affect one's being toward better for action and more healthy, which is already in the direction of skills. But round where it typically connects with skills is like in the curves of the branches of bushes and trees or in a twinding path: fromone situation you see clearly how it develps to a new one, even if it is a complex thing to conceive. With high skillone alsonotices motivational factors and how feelings connect to them,so slight curves, sometimes bigger ones too, are typical to the rythms of action perceived with all one's perception ability,also social eye, atmospheres, sight, movement, etc
A ball is along the same direction as round forms but a different things, since it is a fixed shape that often comes because some nations have a ball in their flag, kind of piece of the vocabulary there and symbolizes propably many valuable things. A ball is different also in it's unifiedness, in a way it is a model of a healthy strong whole which is also healthily according to feelings and happy. So it is a basic model of how things should be, but the grounds are complex and demand for example an understanding of the nature of health and naturality and of how feelings connect to those. It also comes better via understanding several size classes and not just oen at a time.
From the usefulness of round forms it is clear that too fixed rythms like in strainght lines or too arupt changes of phase like in square forms are not good for action and not good for thinking either, do not bring as much understanding. On the other hand square forms are handy in building, since one can lay square blocks of different sizes and materials next to eaxh other and get an unified structure, for example a house. But in building work it is also so that buildings are meant for certain use, so the comfortable spaces as sensed are a good model of how to build and not some measures in centimeters or so.