Step 15: Darken the curved line on the top, left side of the head for the first part of the yak's horn. Draw a similar curved line at the bottom to make the shape of the horn thicker. Keep the top pointy. Part of the bottom of the horn will be blocked by the ear. Draw the horn on the right side the same way. First darken the guide. Then add a second curved line at the bottom to thicken the shape of the horn.
Step 16: Use the initial shapes and lines as guides to draw the rest of the yak's head. Draw a series of short strokes along the outer edges of the initial guides to create the shape of the furry head. Add strokes along the bottoms of the horns to create a furry base. Make the bottom of the head narrower. Add some strokes inside, at the top, for the furry head. Add some strokes near the middle of the yak's head to emphasize the shape of the muzzle.
Step 17: Use the second line from the right as a guide to draw the first front leg. Follow the path of the guide and lightly sketch the shape of the leg around it. When you get the leg right, darken the lines using a series of short strokes for the fur. The longer you make these strokes, the shaggier the yak's fur will look. Make the hoof at the bottom blocky. At the tip, draw two angled lines to split the hoof.
Step 18: Use the line on the right as a guide to draw the other leg the same way. Draw the shape of the leg around the guide and use short strokes for the shaggy fur. Add the split hoof at the bottom. The top of this leg will be hidden behind the yak's body, so don't draw it.
Step 19: Use the line on the far left as a guide to draw the first hind leg. Just like the front legs, first sketch the shape of the hind leg lightly around the guide. When you get the leg right, darken the shape using short strokes for the fur. The top part of the leg should be wide, while the foot and hoof should be skinny.