Hi Chris, i think the problem is that you are misunderstanding the relationship between the lines, you're thinking in 2d rather than 3d. In the third head of the example the numeration is misleading, line number 4 should be the one underneath the nose and line number 2 should be the one from the ear to line number 3. In the two pages i attached he exemplifies the 4 line approach in a clearer way. Think like this, line number 2 represents the side plane of the face, line number 4 represents the front plane of the face and they meet on line number 3, which is the edge of the cube or where the face "turns". Hope i was able to help, keep up the good work!