The ornamental design for a diffuser for tubularskylight, as shown and described.
FIG. 1 is a front perspective view of a first embodiment of my new design for a diffuser for tubular skylight;
FIG. 2 is a side elevational view of the embodiment depicted in FIG. 1;
FIG. 3 is a front plan view of the embodiment depicted in FIG. 1;
FIG. 4 is a back perspective view of the embodiment depicted in FIG. 1; and,
FIG. 5 is a back plan view of the embodiment depicted in FIG. 1; and,
FIG. 6 is a front perspective view of a second embodiment of my new design for a diffuser for tubular skylight. FIG. 6 is identical to FIG. 1 with the only exception being the lines added to FIG. 6 to show reflective surfaces. All other aspects of this second embodiment are identical to the embodiment disclosed in FIG. 1 through FIG. 5.