FIG. 1 is a perspective view of a step stool showing the new design with the texturing on the top surface shown in broken lines and form no art of the claimed design;
FIG. 2 is a front elevational view thereof, the rear elevational view being identical thereto, with the wheels supporting the step stool shown in broken line;
FIG. 3 is a side elevational view thereof, the unillustrated side being identical thereto, with the wheels shown in broken lines;
FIG. 4 is a top plan view thereof, with the surface texturing of the top horizontal surface of the step stool shown in broken lines as such texturing may vary and does not form a part of the design to be patented; and,
FIG. 5 is a perspective view showing the open bottom and interior of the step stool with structural elements shown in broken lines as they do not form a part of the design being patented.