FIG. 1 is a perspective view of the step stool, incorporating the new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof; and

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top view of the step stool; and,

FIG. 7 is a bottom view of the step stool.

The broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design.