Monte Carlo is a pair-matching card game (using a deck of 52 playing cards) where the objective is to remove cards in pairs from the tableau.

At the beginning in the game 25 cards are dealt to a 5x5 grid. Remaining cards are set aside forming a stock pile. Two cards of same rank can be discarded to the waste pile if they are placed next to each other horizontally, vertically or diagonally. Discarding cards creates gaps in the grid. After removing all matching pairs, remaining cards can be condensed in the grid (moved left and then up) so that all gaps are moved to the end. Empty gaps can be filled with cards from the stock pile.