so when the marbles roll down the 2nd hill they 'pull along' the flow on the first hill, making it go faster than it would just due to gravity

My God, man! Don't publish such dangerous information. Don't you realize what you've done?

The magnets/marbles in the second plane accelerate the marbles in the first plane, which in their turn accelerate the marbles in the second plane -- an open ended positive feedback loop. As the marbles approach the speed of light, their mass will increase, eventually reaching enough density to turn into a black hole which will swallow up the whole world and everybody on it.

It's very dangerous to even talk about such things! If some lunatic bent on world destruction were to read this forum, I shudder to think of the consequences.

tanstaafl.