An article of manufacture includes a wall portion having a wall inner surface and a wall outer surface, a base portion having a base inner surface and a base outer surface, at least a portion of the wall portion and the base portion forming a vessel to retain fluid therein, at least part of the base portion configured to receive heat, and a plurality of shaped portions with at least three sides extending above, each shaped portion of the base inner surface including at least three sides and polygonal shaped tops, each of the plurality of shaped portions capable of supplying heat from the sides to fluid adjacent to the sides, the plurality of shaped portions including the polygonal shaped tops to induce creation of a plurality of hexagonal convection cells in contact with a surface of the fluid which increases heat transfer from the heating source to the fluid.