Skip Suva is a fidgeter. When he worked at paper-intensive administrative jobs, he’d doodle incessantly; when he started a coding career last year, he took up fiddling with an SD-card reader that made pleasant snick noises. “Popping the SD card out and clicking it back in,” he laughs. His fidgeting can seem like a crazy tic, Suva admits. But it helps him focus.