I'm not a big fan of posters nowadays, they seem to be more cut/paste photoshop works as opposed to creative and original ways of getting you excited about a movie. BUT. What I wanted to point out in this Hulk poster is the asymmetry in both Edward Norton's and the Hulk's body. Even though both just stand there, none of their arms have the same pose, same for the hand, fingers, shoulders and even the head favors one side.
In animation you want to avoid twinning, so says the common rule, although I think twinning can be effective if done right (with a slight offset so it's not completely mirrored). Someone had a great post about that, but I can't remember who, it was a clip with Simon Pegg in it, anybody remember?. [It can be found here, thanks Jeff!] But again, as a general rule you want to avoid it and Shawn Kelly has a great article about it @ Animation Mentor, check it out.
But let's get back to Asymmetry. Draw a line in the middle of this poster and look at how each side is slightly different. Hulk's screen left shoulder is up, which helps with the different position of his arm, the head is tilted screen right instead of just staying in the middle, etc.
It's a lot more subtle with Edward Norton, but each side is still a little bit different.
So keep that in mind when you get to a moment and pose which looks too mirrored or twinned. - poster found @ impawards