Flask

FIG. 1 is a front, top, and right side perspective view of a flask showing our new design;

FIG. 2 is a front, bottom, and right side 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; and,

FIG. 8 is a bottom plan view thereof.

The broken lines illustrate features of the flask that form no part of the claimed design.