Book excerpt: Imagine someone gave you a sackful of money and told you to build a roller coaster. You'd definitely want it to be the best roller coaster in the world. But how do you go about designing THAT? Armed with your own imagination and some smart research, find out how you can transform a fantasy design into an actual dream product. You'll apply real-world design considerations to your ideas, refining your design to make it workable and achievable as it takes shape.