The ornamental design for a screen for a gutter, as shown and described.
FIG. 1 is a top, back and side perspective view of a screen for a gutter embodying my new design.
FIG. 2 is a detail view thereof taken along line 2 of FIG. 1.
FIG. 3 is a side view thereof, the opposite side being a mirror image.
FIG. 4 is a top view thereof.
FIG. 5 is a front view thereof.
FIG. 6 is a back view thereof; and,
FIG. 7 is a bottom view thereof.
The cross hatched pattern shown as surface shading on the screen represents a continuous mesh pattern as can be seen in the detail view of FIG. 2 that is uniform throughout the surface. The broken line 2 in FIG. 1 forms no part of the claimed design.