Here's a lovely new (old) project from hartleyhair. Indeed, raking sand around DROD elements does make for some quite interesting puzzles.
I wasn't much interested in the Spring rooms, as I solved them pretty much haphazardly. This may be because I hadn't played the original Zen game that inspired this hold, and wasn't aware of an additional restriction in the original game: described in the Architecture thread
here. The Spring level as well as some later puzzles definitely would have been more puzzly if I tried to follow the original rules.
In the later levels where some really neat DROD-Zen hybrid puzzles start to show up. My favorite rooms are: Summer 1N, Autumn 1N1W, and Winter 1W. I wouldn't mind seeing some more Zen levels in the future.