The Fort of Gold (金の砦) is a solitaire game in which you take on the role of a sorcerer manipulating mana to collect seven treasures. There is one deck of treasures and one of magical spirits. Spirits and treasures both have a set of three elemental symbols, where each symbol can be one of earth, air, fire, or water. In order to collect a treasure you need to create a set of one or more spirits that can match with all the elements on the treasure.
However, you may not be able to collect any of the treasures initially exposed. In that case you can swap the exposed treasures or peek at and rearrange the deck, but these both require more demanding combinations of elements.
You win if you can get all seven treasures, but you lose if you're stuck without any legal actions. Can you activate all the spirits before your mana runs out?