Even for some delicacies we need ovals to draw them.
Exercise 1: Draw the disposable cup (containing an invisible tasty smoothie) and/or the frying pan with pancake batter. Because these objects are not transparent, we can only see part of the oval shape of the bottoms and only a part of the warm pancake!
Exercise 2: Look at these two cups of hot chocolate. The more you look at the cup from the side, the flatter the ovals become. Because the cup is not transparent, we can only see part of the oval of the bottom and of the chocolate milk itself! Draw one of the two cups.