Designers of jigsaw puzzles certainly have a tough job. To begin with, they have to look through many kinds of pictures to find one which suits their purpose. Such a picture, however, is very difficult to find. The picture must be of very high quality so that it remains clear when it is enlarged. Also, it must not contain too much of one color, since the puzzle would then be too difficult to put together. Therefore, the task of finding just the right picture often takes much time and effort.