Seven Devils is arguably the most difficult of all solitaire games. It is a two pack game widely available as a computer version.
28 cards are dealt out to seven diminishing columns with the bottom card of each column face up, and a further seven cards (the "devil") are dealt face up to the right of the columns.
The aim is to move all the cards into thirteen-card sequences on the goal piles (at the right of the board), ascending in sequence and following suit, starting with the Aces.
Cards on the table can be stacked red-on-black in descending sequence. Any card can be used to fill an empty column.
Only one card can be moved at a time, but if there are empty columns multiple cards can be moved as if the empty columns were used as temporary spots.
The seven devils in the right-hand stack cannot be placed on other stacks, and can be moved only to the goal piles.
The difficulty of this game arises from three factors
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