“LET’S MAKE A GAME! You’ve built all sorts of small circuits in this book, and each circuit was designed to teach you a particular concept. In this chapter, you’ll combine all your new skills to build a reaction game. The game has a row of five LEDs that light up one at a time so that a light appears to run back and forth. The goal of the game is to stop the light when it’s in the middle of the five LEDs. That gives you 10 points. If you stop it on an LED next to the middle one, you get 5 points. But if you stop it on one of the end LEDs, you lose all your points and have to start over from 0. Try to reach 50 points! You can play this game by yourself to practice your reaction time, or with as many friends as you want. If you’re competing with friends, I suggest giving each player only one attempt at stopping the light before the next player gets a turn.”