The card game idea discussed in my previous post was neither my original intention nor my original idea when I began thinking about partnerships in board games. I wanted to move away from card games, but the hidden information mechanic that is inherent in them made it easier to think in that space.
There is something different about a board game that separates one from card games. Perhaps they can have richer themes. Perhaps relaxed limitations on components can create for a deeper strategy space. Perhaps there is something more enjoyable about manipulating the wooden/plastic components. Whatever it is, I think it would be hard to deny that it is certainly a different experience.
Regardless, I wanted to introduce the partnership play as something that affects what is occurring on a shared board. Each player would hold some cards that would be combined with other players' cards to trigger some event or modify the board in some way. Immediately I began to picture a game where each player is acting as a deity controlling the environment in which one or several civilizations are forming.
The board is a discrete map (square or hex grid) that is seeded with tiles or markers that indicate whether the land is barren, fertile, or flooded. The civilization is represented by meeples that can occupy these spaces. Periodically (after a turn or a round of turns), the civilization can grow, shrink and/or relocate depending on their occupied and adjacent terrain. Before that happens, the players change the terrain by casting spells.
The players cast spells by completing a set of three colors that define the spell. The first player plays a card with the name of the spell he wishes to cast. This card is also one of the three colors in the spell. The next player must play another color in the spell, and the third player (the first player's partner) must complete the spell. Once completed, the spell affects a given area of the board -- perhaps each player has an avatar which he can move to indicate what area the spell will affect. After the board has been modified, the fourth player begins the next spell.
That's how I imagine the "happy path" play of the game. Where the game would get more interesting is if the players had ways to counter-spell, or boost spells. Rules would also have to be defined how to handle a player's inability to contribute to a spell. There are also thematic issues as to why one deity would contribute to another deity's spell assuming that it would be detrimental to him. Other open questions include whether it is one civilization of which all deities are vying for control, or whether there are separate civilizations that each deity is attempting to make the dominant civilization; and also the ever-troubling question of what an end-game condition would look like.
I hadn't consider this until I read Lewis Pulsipher's post on god games, but there is likely a bit of an influence from Molyneux's Populous in my idea. It's probably been more than a decade since I've played that game on my SNES (for hours straight!), but I'm sure the experience has affected my design subconscious.
I'm not sure whether I like the idea enough to put the effort in place to try to solve some of the unanswered questions. My best bet would be to mock up a prototype, and give it a try with the understanding that it wouldn't be a good game. At least then I might be able to recognize the parts worth keeping and narrow down what needs to be improved upon. If only I knew which of my design ideas were worth my limited "hobby time".