In the immediate pre-Christmas class at the community centre we tackled a snowy scene. I had seen something like this on Pinterest and reinterpreted it for the class project. It is a great exercise with the layering of each stage over the previous  with ever darkening colour tones.

I attach my original and a selection of the classes work. it never fails to amaze me the variations you can get in an exercise like this when everybody watches the same demonstration and has the same picture at hand to copy. Fabulous!