WTF?!: marc by marc jacobs

i am slightly in love with the marc by marc jacobs fall 2008 line, but i will go into more detail when i do my fall 2008 new york fashion week posts. for now i would just like someone to please explain this out fit to me. i am just confused. at first i am like oh weird blue sweater underneath but whatever. then i took a closer look and could not for the life of me figure out where it was coming from. there is seemingly no top to it. please someone let me know what the hell is going on. is it attached to the shirt or maybe the vest or even the jacket???? someone just figure it out so i don't loose to many nights of sleep trying to solve this mystery...