Planet Mad

As I recall it, there's a famous philosopher who decided that it was logically impossible to shoot an arrow into a target because firstly the arrow would travel half the distance, and then half the remaining distance, then half the remaining distance and so on, never actually reaching its destination beause there's always another half-distance to go. I suspect the bloke was a Greek, but I'm not certain; I'm sure there are others out there who can confirm this. Regardless of who he was and where he came from, his theory seems to apply to my pile of marking, which gets smaller by the hour but never seems to go away completely.

(For all the Pratchett fans out there, the arrow paradox features in one of the Discworld books, but I can't remember which one... I fear that a surfeit of tea has addled my braincell)