The ornamental design for a tri-light fixture, as shown and described.
FIG. 1 is a perspective view of the tri-light fixture, showing our new design;
FIG. 2 is a front elevation view thereof, the rear elevation view being a mirror image;
FIG. 3 is the right side elevation view, the left side elevation view being a mirror image;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a bottom plan view thereof.
The break lines in FIGS. 1, 2 and 3 are to indicate that the appearance of any portion of the chain between the break lines forms no part of the claimed design, and the broken lines showing the light bulbs in FIGS. 1 and 5 are for illustrative purposes only and form no part of the claimed design as well.