Abstract marks use a single shape or symbol to represent a brand or product. Their genius is their simplicity as customers recognize abstract logos at a single glance. The Nike swoosh, the Apple apple, and the Adidas three stripes are all successful abstract marks. Word marks use words to display a brand or product name. Apple, Starbucks and Burger King are all word marks that successfully differentiate their brands from competitors. Pictoral logos work like an abstract mark, but in place of a word there is an illustration. McDonald's golden arches and Bank of America's umbrella are great examples of visual logos. Letter-based logos include logos where each element in the logo is based on a letter of the company name or a letter of an acronym, for example FedEx and Dogfish Head Brewery are both examples of companies who have utilised letter-based logos to brand their companies.