The sample code was badly broken in areas I wasn't supposed to touch - I did not enjoy the exercise at all. I asked a lot of questions (I was encouraged to ask questions by email) and came up with a solution that sorta worked given all the limitations imposed on it. I think the exercise was more about making the best out of a bad situation (though unintentionally so), so in that sense it was a reasonable sort of exercise. I explained all the problems my solution had and we had a good conversation about it.