This document provides information about peripherals, input and output devices for computers, Wikipedia, QR codes, and customizing backgrounds on Twitter. It defines peripherals as devices connected to but not part of the computer like keyboards, mice, printers, and describes common input and output devices. It discusses the origins and popularity of Wikipedia and how QR codes work and where they can be found. Finally, it cautions about allowing third party sites to customize social media profiles and recommends doing it yourself instead of signing up or downloading anything.