Step 10: Inside each of Jack-Jack's eyes, draw a small circle for the irises. The irises should be pretty close to the inner edges of the eyes. Inside each iris, off to the side, draw a tiny circle to represent glare. In the middle of each iris, draw another small circle and shade them in for the pupils.
Step 11: Draw a small, curved line directly where the construction lines meet for the top of Jack-Jack's nose. Underneath, draw a couple shorter, curved lines for the nostrils.
Step 12: Use the horizontal construction line as a guide to draw the bottom part of Jack-Jack's mask. Follow the basic path of the guide but make the line for the mask wavier. High above the eyes, draw a couple of arcs for the top part of the mask. The top of the mask should follow the curvature of the eyes. The line should dip and meet in the middle. Connect the top and bottom part of the mask using curved lines on the sides.
Step 13: Under the nose, draw a short, curved line for the top part of Jack-Jack's mouth. Draw another curved line underneath the dips even lower, for the bottom part of the mouth. Add short smile lines on the corners of the mouth. Inside the mouth, draw two curved lines for the tongue.
Step 14: Use the C- shaped lines on the sides of the head as guides to draw Jack-Jack's ears. Darken the guides but make the shapes a bit more angular. Inside each ear, draw an angled line for the inner structure.