FIG. 1 is a front, right, top perspective view of a first embodiment of a doorbell showing our new design;
FIG. 2 is a rear, left, bottom perspective view thereof;
FIG. 3 is a rear, right, top perspective view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a left-side elevation view thereof;
FIG. 7 is a right-side elevation view thereof;
FIG. 8 is a top plan view thereof;
FIG. 9 is a bottom plan view thereof;
FIG. 10 is a front, right, top perspective view of a second embodiment of a doorbell showing our new design;
FIG. 11 is a rear, left, bottom perspective view thereof;
FIG. 12 is a rear, right, top perspective view thereof;
FIG. 13 is a front elevation view thereof;
FIG. 14 is a rear elevation view thereof;
FIG. 15 is a left-side elevation view thereof;
FIG. 16 is a right-side elevation view thereof;
FIG. 17 is a top plan view thereof;
FIG. 18 is a bottom plan view thereof;
FIG. 19 is a front, right, top perspective view of a third embodiment of a doorbell showing our new design;
FIG. 20 is a rear, left, bottom perspective view thereof;
FIG. 21 is a rear, right, top perspective view thereof;
FIG. 22 is a front elevation view thereof;
FIG. 23 is a rear elevation view thereof;
FIG. 24 is a left-side elevation view thereof;
FIG. 25 is a right-side elevation view thereof;
FIG. 26 is a top plan view thereof;
FIG. 27 is a bottom plan view thereof;
FIG. 28 is a front, right, top perspective view of a fourth embodiment of a doorbell showing our new design;
FIG. 29 is a rear, left, bottom perspective view thereof;
FIG. 30 is a rear, right, top perspective view thereof;
FIG. 31 is a front elevation view thereof;
FIG. 32 is a rear elevation view thereof;
FIG. 33 is a left-side elevation view thereof;
FIG. 34 is a right-side elevation view thereof;
FIG. 35 is a top plan view thereof; and,
FIG. 36 is a bottom plan view thereof.
The broken lines shown in the drawings depict portions of the doorbell that form no part of the claimed design.