A signal arrow is a special kind of arrow that helps people know which way they should move or drive. It's often seen on the road, especially at intersections or places where cars need to turn. When the light is green and the arrow is pointing to the left, for example, it means that people should turn their cars to the left. Similarly, if the arrow is pointing to the right, they should turn to the right. It's like a guide to help people drive safely and avoid getting into accidents. Think of it like an invisible robot friend who tells us which way to go.