He played the viola in the Thames Vale youth orchestra, which he described as a formative experience: "I'd been in school orchestras and never seen the point. But in Thames Vale I was suddenly with all these 18-year-olds who could actually play in tune. I remember thinking: 'Ah, that's what an orchestra is supposed to sound like! Greenwood also spent time programming, experimenting with BASIC and simple machine code to make computer games. According to Greenwood, "The closer I got to the bare bones of the computer, the more exciting I found it."