FreeCell

Goal: build all four foundations up from Ace to King, each in a single suit.

• Tableau columns build down in alternating colour (e.g. a red 6 on a black 7).
• You move strictly one card at a time. A run already in alternating-colour order can be dragged as a group, but only as many cards as you could move by hand: (1 + free cells) × 2 for each empty column. Free a cell or clear a column to move a longer run.
• Each of the four free cells holds a single card — use them as temporary parking.