Three years ago I got involved with GameJam in Alicante and got assigned the task of making their poster for the GameJam that year.
During a GameJam you should put together a game in less than 48 hours, individually or in a group.
So the basic idea of the poster was to show the progress of making a game from a paper sketch to a real game.
This poster was posted all around Alicante that year. Unfortunately I couldn't participate my self.