Step 20: Use the line on the far right as a guide to draw the first hind leg. Draw this leg the same way. Follow the path of the guide and lightly sketch the leg around it. This leg should be wider at the top than the front legs. The top should also slope to the right. Curve the lines near the middle for the joints. When you get the shape of the Boston terrier's leg right, darken the lines. At the bottom, add the toes and nails using short, curved lines and tiny triangular shapes.
Step 21: Use the last line under the body as a guide to draw the Boston terrier's other hind leg the same way. Lightly sketch the leg around the guide and only darken the lines when you get the shape right. Add the toes and nails at the bottom like before. The top part will be hidden behind the dog's body.
Step 22: Use the remaining lines and shapes as guides to draw the rest of the Boston terrier's body. Simply darken the outer edges of the initial lines to create the shape of the body. Curve the line at the bottom for the chest. Don't overlap the legs that are on this side of the body. On the top, right side of the body, draw a couple of short, curved lines for the dog's curly tail.
Step 23: For a cleaner look, erase as much as you can of the initial guide lines. Don't worry about erasing all of the guides. It's okay to leave some behind. Re-draw any final sketch lines you may have accidentally erased.
Final Step: Outline an area around the Boston terrier's eyes, chest and legs that will separate the classic black and white markings. Use a dark value to create the black markings on the body. Add the value lightly at first and slowly build it up. Vary the pressure on your pencil to get different degrees of tonal value. This is an easy drawing to shade because you don't have to worry about fur. Just fill in the areas with dark value. Adding the value can still be time-consuming, so be patient and take breaks. Use lighter value under the dog's nose. For a more detailed guide on how to shade, check out this tutorial: How to shade.
It's a good idea to use reference as you draw for an accurate depiction of a Boston terrier. If you have a pet Boston terrier or a similar dog breed, try to duplicate its pattern on your drawing. Using a light value, add some shadows to the white areas of the body to give the figure more volume. Add a cast shadow underneath to ground the dog. Don't forget to pause the video to draw at your own pace.