Add another global variable for the player, called a hand. Make the hand initially empty. Change the description so that there is a “key” in the Living Room. If the player types the command key while in the Living Room, the key gets put in the hand. Now, if the player has the key when entering the Kitchen, the stairs become accessible, allowing the player to go “west” and up the stairs. You will have to add some rooms to the game to make this work.