You folk could post a bit more - I'm feeling considerably unloved. Anyway, the solution:
Take the golden symbol from each fire dome, and map it to the colors of the lights on Survey Island - the buttons that turn on the lights are adorned with those eyes. Next, find out the "grid" location of each dome by locating the beasts on the topographical maps. Finally, put each dome's associated color of marble on that dome's coordinates on the board. Then step back, push the button, and appreciate the contained explosion of directed power that fuels your teleportation betwixt worlds. The Fire Dome puzzle (also called the Waffle-Iron puzzle, which is vaguely what the grid device looks like) utilizes the player's ability to freely explore the islands, and encourages the mutual dependence each location has on another.
So, now we'll talk about that free-formliness. At some point yesterday, I had an idea. Riven, like Myst, Exile, and Revelations, is a node-based game,which is to say that the player can click on particular areas to move to them, and then turn about and see things from that node. Exile does this system best, allowing full three-dimensional spinning without clicks, but Riven's system is acceptable. Anyway, the idea was to make a map of Riven, marking each node, and listing the minimum number of clicks it would take a player to reach that point. Surprisingly, at least in my opinion, that number is low fairly universally. The island of Myst would have a low number (as the island is pretty open), but the other Ages in that game would have fairly linear progression of points until the Age's end.
Riven is an exploration dream, in a sense. Very little has to be solved to explore almost the entirety of four of Riven's five islands (Prison Island, though, requires the Fire Domes to be activated). Even the spot of the game's end can be reached in (I believe) two clicks, and with save "abuse," the game can be ended in about thirty clicks, albeit with a fairly unsatisfactory version of said ending.
Which, I suppose, brings me to the next point - this freeform nature allows for the player to screw up the canonical plot in a number of ways. What if you signal Atrus before you kill Gehn? Before you find out about Catherine's state of affairs? What if, stuck on a puzzle, you decide to pull out the Prison Book, and see for yourself what's inside? What if you did so with someone already in there? The game deals with all of these situations, providing endings that range from vaguely amusing, to chilling, to tragic. There are ten endings to the game, and in four of those you get shot. Each of the nine bad endings requires you to do something rather counter to your directives to discover, but after a first playthrough they are fun to try to "collect."
Gehn shoots you - but the game allows for no violence by players. That's always been a must for the Miller brothers, the creators of the Myst franchise, a sentiment which has lasted even
through the MMO Myst game, Uru Live (which is, by the way, great fun with a great group of people. I really need to play it again). Violence in puzzle/adventure games has always disappointed me. In The Longest Journey, they sidestepped the issue by having threats never actually harm you, which I found to be really lame. In that game's sequel, Dreamfall, the "violence" sections were like fighter games without the fun, and were tedious and out of place. In the Trilby games, only Five Days A Stranger did a good fight scene - a single affair with an autosave, a single action needed to save yourself, and a strong satisfaction for saving Trilby from harm. In later games, repeatedly running away from possessed corpses etc. got annoying as hell, especially when they cheated, teleported ahead of you, and claw you just as you're about to enter the next room, where temporary safety lies. On Myst's side lies the Neverhood, where Klayman can only die by doing the most stupid and irresistible action in the game - an hilarious ending, if I may say so.
In short, don't do violence in this sort of game, unless it's short, sweet, and the player's character is on the receiving end. I rather like the pacifist protagonist in these games, a feeling which oddly is amplified by a scarcity of NPCs. Riven has maybe fifteen NPCs in all, all but four of whom occupy but a few moments of screen time, and are there to remind you that the world you are inhabiting isn't a vacuum, but rather a home for these people. The appearances can be genuinely frightening, too, for a person who's been exploring for hours alone. I know the first time I saw the little girl I jumped in my seat.
To get back to the first point, this game's extreme nonlinearity is a great asset to the game. For any endeavors of this sort that I would work on, I would take Riven's game design as a model to follow: give an interconnected game world that they are almost never barred from re-exploring completely at their leisure; give the game's setting plenty of internal consistency and realism, finding purposes for everything and creating pieces of setting for the sole purpose of expressing atmosphere and culture; and make knowledge a primary commodity in the game, some of which is randomized per playthrough, some of which is not, to make gamers both feel challenged in later playthroughs, and rewarded for remembering obscure or complicated facts.
Final notes on that last point: there are three combination locks in the game, all of which are randomized from the game's start. This is why the twenty-click playthrough requires you to load a save: a critical code to complete it is stored about halfway through the game, and even the best players can't predict it until they find it. Because of these combinations and because of the more complex but static nature of the real puzzles, games of Riven range from several weeks to fourteen minutes and thirty one seconds. Compare to the three minutes eighteen of Myst (which is really done in a minute fifty), and I think you'll see why Riven's superior to them. All the links except for the first contain spoilers.
Next time, some nit-picking. A little spoilery, but I'm going to go over the game's worst bits as far as I remember them.