Describe the image of D first reflected across line l, then across line m.

Unfortunately, I cannot accurately describe the image as there is no context provided for what the initial position of point D is, how line l and line m are positioned, or what their orientations are. Please provide more information or a description of the positions and orientations of the lines and point D.

To describe the image of point D after being reflected across line l and then across line m, we need to understand the process of reflection and how it affects the position of a point.

1. Reflecting across line l:
- Draw a line perpendicular to line l at the point of reflection (let's call it point A).
- Find the intersection of line l and this perpendicular line (point B).
- Measure the distance between point D and line l and extend it on the other side of line l (denoted as point C).
- The reflected image of point D across line l is the point C.

2. Reflecting across line m:
- Follow the same steps as above to reflect point C across line m.
- Draw a line perpendicular to line m at the point of reflection (let's call it point E).
- Find the intersection of line m and this perpendicular line (point F).
- Measure the distance between point C and line m and extend it on the other side of line m (denoted as point G).
- The final image of point D, after reflection across both line l and line m, is point G.

By following these steps, you can visualize the process and locate the image of point D after being reflected across line l and then across line m.

To accurately describe the image of D after being reflected across line l and then across line m, we need to consider the following steps:

Step 1: Reflecting D across line l:
You would imagine a line perpendicular to line l passing through point D. The reflected image of D across line l would be located on the other side of line l, maintaining the same distance from line l as the original point D.

Step 2: Reflecting the image across line m:
You would imagine a line perpendicular to line m passing through the reflected image of D. The reflected image of D across line m would now be located on the other side of line m, maintaining the same distance from line m as the previously reflected image.

Overall, the final image of D after being reflected across line l and then across line m would be the point obtained in Step 2.