illustrates the third type of motion, the moving pattern.
We distinguish between a moving pattern and a moving spot or line, because a pattern relates its separate elements to each other. This relation may or may not change as the pattern moves. Thus the V-shaped pattern formed by the flying geese may become sharper or flatter, or one side may be stretched out longer than the other, as the flight continues. All fixed pictures are patterns which do not change in form while we look at them, and the pictorial principles therein involved have been thoroughly discussed in the preceding chapters. But if the director wants a pattern to move to the right or left, up or down, away from him or toward him, or to change its character gradually, then a new problem of composition arises, and the solution of this new problem is both inviting and perplexing.
It is inviting because there are so many patterns which gain beauty from motion or change. A fixed circle is not so appealing to the eye, for example, as a rolling hoop. A wheel standing still is not so fascinating as one that rotates, like the wheel of a wind mill, or one that rolls, like the wheel of a carriage. Thus also the pattern formed by the rectangular shapes of a train standing still does not please the eye so much as the harmonious change in that same pattern when the train swings by us and winds away into the distance.
The patterns which may be compared with mathematical figures, such as circles, squares, triangles, diamond shapes, etc., are not the only ones. We are simply mentioning them first to make our analysis
