Another warmup piece: The Entrance.
Early morning warmup: Alien visitor.
For a majority of projects, I usually jump in and start breaking down the brief/script according to the scheduled project time, and start drawing almost right away. Once in a while, for a few projects, and for various reasons, I prefer to just let the story sink in, do some top level thinking a little bit, work out the visuals, compositions and sequences in my head, then after having identified a clear/preferred path I want to take, I start drawing. During the prep period, I may do a few warmup or test boards just to have a feel for what I want to do in the project.
This is one of those warmup/test boards. Sometime it can be in rough form, Other times I carry it to what I consider fully rendered and finished condition.