But if the objects are slightly apart, they have the opposite, or repelling force and they start to push away from each other. These are tools you can use to create interest and focus. Balance is achieved by composition, framing, and interaction of the line, the shapes and the tonal values. Both lines and shapes need to be interesting. They're either thick or thin, dark or light, and so you know that the variance you have causes more interest.
Lines cause different moods, and they dominate space differently.
They cause direction. Lines are referred to as 'contours', and the definition of a contour is like the outline or the boundary that separates. Lines divide space into shape. There's the principle called The Golden Rule. It deals with proportions and has been around since antiquity.