I spent some time over lunch a few days ago sketching these windmills.
Then I spent the following days fixing the sketch.
At first I had the values all wrong and didn't have enough contrast in the sky.
Then I had serious problems with perspective on the blades. They were constantly spinning when I sketched them so it was hard to "pause" them to get a good idea of how long each would be.
I ended up reworking it all at home and I think I came pretty close to something I like. Nothing will ever be perfect and it's time to move on.
It's a bit tighter than I usually do and that was fun to experiment with. I even tried a ruler with the stylus which worked ok but in the end I kept freehanding the blades as I worked on angles and such.