Two worlds are overlayed on top of each other - a red one and a green one.  There are also two 'worms'.  When the red worm intersects green life, it transfers it to the red world.  When the green worm intersects red life, it transfers it to the green world.  Life is colored based on the amount of life around it, in its own world.  Not sure how it's going to look on the big display or that I'm happy with it, but it works.