(1) your goal is to get rid off all the cards, except the four aces. you win the game if the aces are the only cards left on the table when the deck is emptied, and one ace lies on top of each of the four card piles.
(2) to get rid of a certain card, it must be visible on the top of either one of the card piles, there must also be at least one other card of the same suit, but of higher rank visible on top of another card pile.
(3) when a card pile is empty you can move a card from another pile to that one.
(read more) wikipedia, wikibooks (swe)
controls: 1, 2, 3 and 4 to access the cards (press and/or hold), d to deal and r to restart game. or use mouse to drag and drop and doubleclick.