A Set is a card that defines a group of cards.
Any given card belongs to multiple sets. For example, the card named Wiki on Wheels is a member of these three sets:
Each Set card offers a convenient interface for viewing and editing related Rules. For example:
There are currently eight kinds of sets. From broadest to narrowest, they are:
Any rules on narrower set (higher number) will override a broader one (lower number).
For example, suppose you want to have a special layout for a card named "World Map". You can set the layout for that one card with the following Rule: "World Map+*self+*layout". Note that this connects a Set of one card ("World Map+*self") to the Setting "*layout". This rule would overrule any broader *layout rule, such as *all+*layout, because the single card set (#8 above) is narrower than the set of all cards (#1 above).