It uses a standard deck of playing cards. Thirteen cultural influences, laws, or taboos are assigned to the ranks of the cards, and the suit determines whether the character is an exemplar of that influence, or if they invert it in some way, or some other relationship between the character and the influence. I can't recall the details, which is why I'm searching for it. It's not Traveller: New Era or Twilight 2000, both have turned up in my search but they are not it.
The variation of the idea that I'm most familiar with is about five years old and was system independent from the start.
The process was created by Simon Carryer on storygames, in Generating "Culturally Rich" NPCs.
His work inspired Mo, at Sin Aesthetics, to write about it in Simon Says.
In 2012, the mechanic was incorporated into a very cool 24 hour RPG called The Oathbreakers.