Wrong orientation
This was the first sketch for the picture here. All that work, the whole twenty minutes, wasted! Why? Because I failed to recognize that the chosen frame was a former mirror and hence had the hanger on the short side. As it always happens in such situations: it was a cheap frame, everything was glued in place and would have needed way too much work to change. More work, in fact, than the effort to just redo the sketch in a different orientation.
And all that for such a lame lark.
By the way: the dark spots had been done with a very soft graphite pencil but the deep black parts have been done with a charcoal pencil. It just cannot be done in graphite.