The left side of the page, I used a ruler to straighten the lines and using an eraser. The ebony pencil was used to get the darker blobs in the picture. It was also used to create little marks everywhere. The eraser shield was used to create gaps around the picture.
I put emphasis on the lines, that make up the shap of a box. That way one's eyes are automatically drawn towards the middle of the illustration. The lines create different shapes to those who are seeing it.