Eep! It's so long since I've seen it I have erased all memory of celery-eating. I love love love that story, especially all the Escher stuff: was one of the very few moments as a kid where I remember actually 'getting' a cultural reference (my sister had posters of his stuff plastered all over the walls) without having to ask someone.

Where is my dvd of that, eh, BBC? *shakes fist*