You have to email me a drawing of your most 'elegant' Venn diagram that comprises of four regions. Ie, a diagram which most elegantly allows you to diagrammatically represent the possible combinations of four sets.
Ie, if this diagram is an elegant representation of the combinations of 3 sets:
then what would be one for four?
Rule #1: You don't talk about fight club.
Rule #2: No research. This has to come from your own head only. Google and wikipedia aren't your friends this time.