Curved lines are smooth, continuous lines that bend without sharp angles. They can be found in nature, such as the shape of a rainbow or the outline of a tree. Curved lines can vary in tightness and direction, creating different visual effects and feelings. In art and design, curved lines are often used to create movement and flow. They can soften a composition, making it more inviting and dynamic. Examples of curved lines include the arcs in architecture and the swirls in calligraphy. These lines play a crucial role in both natural and man-made environments.