1. **Problem Statement:** Reflect an angle over the line $y = -x$ and explain if it is possible. 2. **Reflection Concept:** Reflection over a line in the coordinate plane means every point of the original figure (preimage) is mapped to a point (image) such that the line is the perpendicular bisector of the segment joining the point and its image. 3. **Reflection over $y = -x$:** The line $y = -x$ is a diagonal line through the origin with slope $-1$. 4. **Formula for Reflection:** To reflect a point $(x,y)$ over the line $y = -x$, the image point is given by: $$ (x', y') = (-y, -x) $$ 5. **Applying to Angles:** An angle is defined by two rays meeting at a vertex point. Reflecting the vertex and the two points on the rays using the formula above will produce the reflected angle. 6. **Conclusion:** Since the reflection formula applies to all points, any angle or object in the plane can be reflected over any line, including $y = -x$. **Final answer:** Yes, you can reflect angles, or any object, in the coordinate plane over any line in the plane.