Step 20: Use the leftmost line as a guide to draw the other hind leg. Follow the path of the guide and use a series of curved lines to represent the muscle structure along the leg. Add the pointy toes at the bottom. Notice that these toes look shorter than the ones on the other leg because they're bent. Follow the guide to draw the right edge of the leg. The shape of the allosaurus' leg should gradually get thicker near the top.
Step 21: Use the initial lines and shapes as guides to draw the torso. Simply darken the outer edges of the initial guide line to create the shape of the body. Draw a series of small triangle-like shapes along the allosaurus' back for extra detail. Make the spikes different sizes for more variety. You can also omit them if you'd like.
Step 22: Darken the guides on the left for the allosaurus' tail. Add a few short spikes along the top edge of the tail too.
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: Add some shading to your allosaurus drawing to give it more dimension and volume. Pick the direction of the light source when shading so that the shadows are consistent with it. Vary the pressure on your pencil to get different degrees of tonal value.
Add a cast shadow underneath your allosaurus. This helps ground the dino so it doesn't appear to be floating.
You can add even more value throughout your allosaurus drawing for extra detail. No one is exactly sure what this dinosaur looked like, so you can shade yours however you'd like. You can even color it! First use a medium value all over the body. Then add stripes or other patterns on top with a darker value. Don't worry about shading too smoothly. The rough value will give the dinosaur's skin a rough, bumpy texture. Shading can be time-consuming, so be patient and take breaks. Don't forget to pause the video to draw at your own pace.