The starting 11 that West Ham have "studied":
Forster, Clyne, Fonte, Yoshida (centre back), Bertrand, Reed, Davis, Ward-Prowse, Tadić, Elia, Pellè
The probable starting 11 vs West Ham:
Forster, Clyne, Fonte, Gardos, Yoshida (left back), Schneiderlin, Wanyama, Davis, Mané, Elia, Pellè
So, that's nearly half the team different from the Swansea game.
In other words, they've been revising biology before taking a chemistry exam (or some other slightly dodgy Trousers analogy)....