This is the cube and the sphere. I get the transitions not so much by varying pressure but by changing the gradation of the pencils.

Drawing the smoot single tone background and the water drops was relatively ok. However, the smooth gradated tone study was a real challenge. Using a tissue to even and merge the tones removes a lot of graphite and I do not manage to make smooth transitions. Also, it looks as if the paper absorbed the natural oil from my fingers, leading to large dark spots difficult to remove.