Time-based board game

As mentioned before, I refuse to bore you with every little mundane detail of my daily life. Normally homework and school related happenings would fall into such a category of being wasted effort if written up. However, this semester is proving to yield interesting projects that I would like share and maybe even get some feedback on.

For my "Game and Interactivity 1" class, our final project is to create some kind of non-electrical game and have it actually be fun and challenging. I have chosen to make a "time-based" board game. That doesnt mean that it must be played in a certain amount of time (though that certainly is possible), it means that the game takes place at different points in time. For example, the game will probably be played on 3 or 4 game boards stacked on top of each other (see picture above) in which actions on the lower boards effect the layout and actions of the boards above them.

My biggest hurdles right now are deciding...
-How much time passes between each board (20 yrs, 100 yrs, 1000 yrs, etc)
-What shape the boards are (square with squares, round with concentric circles, etc)

One cool idea I'm exploring is that maybe the entire goal is to indirectly eliminate your opponent by traveling back in time (going from the top board to the bottom) and killing his grandfather (the Grandfather Paradox).