Step 20: Darken the bottom edge of the small circle for the bottom of the hand. At the top, draw a short, arc for the small thumb. Draw a series of longer, curved arcs along the right edge of the small circle for the fingers. Jack-Jack's fingers should overlap a bit, and they should gradually get smaller toward the bottom.
Step 21: Darken the sides of the initial circle that's under the head to create the body. Add a few curved lines inside to emphasize the shape of Jack-Jack's belly.
Step 22: Darken the guide on the lower, left side to create Jack-Jack's first leg. Make the lines curvier and add a line inside the foot.
Step 23: Darken the guide on the lower, right side to create Jack-Jack's second leg. Make the lines wavier as you darken them for a more cloth- like texture.
Step 24: For a more finished look, carefully go over the final sketch lines with a pen or marker.