FIG. 1 is a top front perspective view of a bubble machine showing the claimed new design;
FIG. 2 is a bottom rear perspective view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a right side elevation view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is an enlarged view of the design features included within circle 9 of FIG. 1; and,
FIG. 10 is an enlarged view of the design features included within circle 10 of FIG. 7.
The broken lines depict portions of the bubble machine that form no part of the claimed design.