We claim the ornamental design for an oval sink with a convex bottom, as shown and described.
FIG. 1 shows a perspective view of the claimed embodiment.
FIG. 2 shows a right side view of the embodiment. The left side view is a mirror image thereof.
FIG. 3 shows a cutaway view of the right side.
FIG. 4 is a front view of the embodiment.
FIG. 5 is a top view of the embodiment; and,
FIG. 6 is a bottom view of the embodiment.
Short broken lines depicting countertop, faucet and drain pipe in FIGS. 1-4 are directed to environment and form no part of the invention. Short broken lines in FIG. 5 indicate the contours of the convex sink bottom.