Threedom

Players:  Two

Equipment:  Standard deck of cards, pencil and paper to record scores.

Object:  Be the first to score a set number of points (usually 500).

Preparation:  Deal 36 cards into nine facedown piles of four cards a piece.  Then flip the piles faceup (squaring them to ensure that only the top card is visible) and put them in a 3 x 3 grid between the two players.  Deal three cards to each player, and place the remaining ten cards in a facedown pile by the grid to form the draw pile. [See setup.]
 

Play:  Players alternate taking turns.  On a turn, a player does three things.   First, he plays any card from his hand onto any of the nine piles.  Then he takes the top card from any other pile into his hand.  Finally, he may be able to claim one or more sets for later scoring.

A set is three cards in a row, column or diagonal which are either all the same rank (e.g. three jacks) or form a run (i.e. three consecutive cards of the same suit, such as 3, 4, 5 of diamonds).  Runs must be in order, so while both "9, 10, J" and "J, 10, 9" are acceptable, "9, J, 10" is not.  If one or more sets exist at the end of a player's turn, he may take all the cards in the sets and place them in front of him (faceup and spread out, so both players can see what they are).  The cards in all the sets are taken simultanously, so if two or more sets exists and they share common cards, the player gets all the cards (even though by taking the cards in one set, he would be leaving the other sets incomplete. [See example.])

If, after taking sets, any of the nine piles are exhausted, the active player must replenish the empty piles by dealing one card from the Draw Pile into each empty space.  Sets created by dealing out cards into empty spaces are not taken my the current player; they are left for the next player to claim.  If there are insufficient cards in the Draw Pile to replenish the exhausted piles, the round ends immediately.
 

Scoring:  At the end of each round, players score:

If either player has a cumulative score of 500 (or whatever the agreed upon target score is) or greater, the game ends and the person with the highest score wins.  If neither player has reached the target score, another round now takes place.  The player who went second in the previous round goes first in the next.