Okay, I promised I'd post the solution to Grow, and here it is. I didn't figure it out myself, of course, though it might have been fun if I had the time. I found it through the miracle of Google at this blog. Block out the following text if you want to know how to reach 20,000 points:

Put the parts in in this order: SPHERE, CUBE, EGG, HILLS, LADDER, PIPE, PROPELLOR, WHIRLWIND, COG, DISH, NOZZLE, TV.

Note that the perfect solution isn't the only interesting result. For example, if you move the whirlwind up in the order, you can turn the mountain to a volcano, which has some pretty funny effects. There's probably other weird stuff still to be discovered.