Calligraphy is considered a high art form in China. Some masters train their whole lives to render script in their own distinctive and beautiful style. It can be hard to understand when you can't read the words, but in general, know that a primary element that is meant to be conveyed is a sense of movement and energy. There are many ways to do it, but one of the most traditional is done with a special horsehair brush dipped in black ink, with a scroll of rice paper as the writing surface. In parks, you might even see elderly men using a giant brush dipped in plain water to write characters on the ground -- a meditative form of exercise.