An e. You can write it with one fluid swoop of a pen or one tap of the keyboard. The most commonly used letter in the English dictionary. Simple, right? Now imagine it printed out millions of times on thousands of forms and documents. Then think of how much ink would be needed. OK, so that may have been a first for you, but it came naturally to 14-year-old Suvir Mirchandani when he was trying to think of ways to cut waste and save money at his Pittsburgh-area middle school. By Madeleine Stix. Read more.