Here is the graph showing the reflection of rectangle $KLMN$ over the y-axis. The new positions of the vertices are labeled $K'$, $L'$, $M'$, and $N'$ respectively.

Would you like to explore more about reflections or any other transformations? If you have any questions or need further details, feel free to ask.

Here are some related topics you might find interesting:

1. How do reflections work with respect to other axes or the origin?
2. What happens when a shape is reflected over a slanted line or an arbitrary line?
3. How can transformations be used to solve real-world geometric problems?
4. What are the properties of shapes that are invariant under reflection?
5. Can you describe a real-world example where reflection symmetry is utilized?

Tip: When studying transformations, it can be helpful to also look at the effect on the shape's area and perimeter, which often remain unchanged in the case of reflections.