Cruel Solitaire is a popular pile based solitaire card game. The goal for moving cards to the suit piles on the right is pretty standard, just build them up from Ace to King by suit. Building down the piles is rather challenging because you have to build them down by suit. The interesting part of Cruel is the 'Shift' button. When you click it, all the cards get shifted over to the left until they form piles of 4 cards again. Since this isn't a random shuffle, the movement is predictable and really adds to the game.