Flame of Olympus Was created by Daedalus Using the Fires of Hades. Read The Notebook Entrys od Daedalus it will explain.
Hades is a vast place just like the pits of Tartarus. Think about it this way, everytime he went to hades he got closer to the center. It just took three tries.
Well that....kinda....and the fact that each game is different. Different designs that fit each game. You wouldn't want to play the same Hades level every game. The designers are different for each game, and the ones that did stay on the team make different looks for every game so each game is unique and has it's own feel and artistic look. Aside from that, Hades is very big. It's highly doubtful that he would be fall into the same place more than once.
I don't think that's right, because if that were so then that would mean that the Flame of Olympus was created to contain Pandora. Which isn't true, because Hephaestus used it to create Pandora's Box (and Pandora) long before Zeus commissioned Daedalus to build the Labyrinth. What I think he was talking about there was the things you put the Wind of Boreas (or whatever its called) into in order to make the cubes of the Labyrinth move.
But thanks for replying anyway. Anyone else got any other theories?