The object of Spider is to clear all the cards from two decks off the piles (1) and the stack (2). Cards are cleared by piling thirteen cards in the same suit from King down to Ace.
Any card may be moved from the top of one pile, to the top of another, building downwards by rank ignoring suit. However a group of several cards may be moved in that way, if every card in the stack is of the same suit. For example the four, three, and two of spades together may be moved onto any five. However the if the two were of diamonds instead, the four could not be moved without first moving the two separately.
Any card or group of cards may be moved to an empty pile, as long as the group of cards follows the same rule above.
At any time yo may click the stack (2) to deal a new card to the top of each pile.