FIG. 1 is a front elevational view of the waterbed sheet showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a perspective view, partially folded back, the broken lines are for environmental purposes only and form no part of the claimed design.