Add to the rule “Cards” a subrule called “Selling” as follows:

Should two Wizards, A and B, agree via private communication that Wizard A will sell one card in their hand in exchange for an amount of Wizard B’s Thaum equal to the score of that card, then either such Wizard may post a comment (called the “purchase announcement comment”) to the GNDT. This commend declares a purchase in progress, names the other Wizard, and names the card being sold. The other Wizard may then, within 24 hours, perform this transaction (with the card moving from Wizard A’s Hand to Wizard B’s Hand and the Thaum being transferred from Wizard B to Wizard A simultaneously) and update the GNDT to reflect it.

The card must remain in Wizard A’s hand, and Wizard B must have at least the required amount of Thaum, until the purchase is performed, or it cannot take place. If the purchase announcement comment is more than 24 hours old, and the purchase has not yet been completed, the purchase attempt is rendered invalid and must be restarted with a new purchase announcement comment if the purchase is still to take place.