FIG. 1 is a perspective view of a first embodiment of my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a perspective view of a second embodiment of my new design;
FIG. 9 is a front view thereof;
FIG. 10 is a back view thereof;
FIG. 11 is a left side view thereof;
FIG. 12 is a right side view thereof;
FIG. 13 is a top view thereof;
FIG. 14 is a bottom view thereof;
FIG. 15 is a perspective view of a third embodiment of my new design;
FIG. 16 is a front view thereof;
FIG. 17 is a back view thereof;
FIG. 18 is a left side view thereof;
FIG. 19 is a right side view thereof;
FIG. 20 is a top view thereof; and,
FIG. 21 is a bottom view thereof.
The broken lines in the Figures illustrate portions of the aroma diffuser which form no part of the claimed design.