With two buttons and an LED, the book explores six basic computer logic gates, including WIRE, NOT, OR, AND, XOR and a LATCH. The book uses light sensors to detect which page is open and change the operands accordingly. Please take a moment to ask yourself honestly if you: have a baby are planning on having a baby are interested in computer engineering will be attending a baby shower in the next 1-6 months have a friend that looks like they might have a baby are planning to be interested in computer engineering know a computer engineer that acts like a baby skipped the first two days of CE150 are learning how to read If you fall into any of these categories, then you should definitely get a few of these.