Bill Atkinson won the respect of Steve Jobs by creating a high-level programming language in just 6 days

• Bill Atkinson died on June 5 after battling pancreatic cancer. He was 74. Atkinson was one of the earliest Apple employees, responsible for key Mac software and its graphical user interfaces. But he ultimately won the respect of his boss, Apple co-founder Steve Jobs, by creating a version of a high-level programming language for the Apple II computer in just six days.

Bill Atkinson, who worked at Apple from 1978—two years after its founding—to 1990, died on June 5 after battling pancreatic cancer, his family wrote on Facebook. He was 74.

Atkinson was the 51st employee at Apple, and he was personally recruited by Steve Jobs. According to Walter Isaacson’s biography of Jobs, Atkinson, a doctoral student in neuroscience at the time, initially declined Apple’s request to come work at the company. But Steve Jobs sent Atkinson a nonrefundable plane ticket, and then gave him a three-hour pitch on why he should join the company.

“Think about surfing on the front edge of a wave,” Jobs recalled telling Atkinson in that meeting. “It’s really exhilarating. Now think about dog-paddling at the tail end of that wave. It wouldn’t be anywhere near as much fun. Come down here and make a dent in the universe.”

Atkinson accepted the job offer—and as a result, he never finished his PhD.

Atkinson would go on to develop some of Apple’s key software, including Quickdraw, which allowed old Apple computers to draw images and windows on the screen, and HyperCard, an easy-to-use software development kit so creators could build their own applications. He also notably developed the graphical user interface of the Apple Lisa, a precursor to the Macintosh, and later several of the Mac’s user interfaces. But his very first job was to develop a program that could track stock portfolios. The software would auto-dial the Dow Jones service to get quotes, and then hang up.

His second project at Apple, though, was ultimately how Atkinson won Jobs’ respect.

Jobs had been resisting using a new programming language for the Apple II, one of Apple’s earliest and most popular personal computers that spawned many successors—including the Lisa, the Apple III, the Apple II Plus, Apple IIe, Apple IIc, Apple IIc Plus—though most of those computers, save for the Apple IIe, were abject failures. Jobs at the time had resisted giving the Apple II a new programming language, thinking BASIC, the simple programming language that powered the original Apple I, was all the Apple II needed going forward. Atkinson, however, pressed Jobs to build something better.

“Since you’re so passionate about it, I’ll give you six days to prove me wrong,” Jobs told Atkinson, according to Isaacson’s biography of the Apple co-founder.

Sure enough, in just six days, Atkinson had created a specialized version of Pascal, a high-level programming language made especially for the Apple II. According to Isaacson, “Jobs respected him ever after.”

Atkinson would later leave Apple in 1990 to co-found his own company called General Magic, which built precursors to USB and small touchscreens. In 2007, he was an outside developer for a small startup called Numenta, which leverages what we know about human neuroscience to develop AI. But Atkinson also spent much of his later years working as a nature photographer, using a digital printing process he helped create, and a mobile app he developed, to let users make postcards out of their digital images to send via postal service or email.

Atkinson is succeeded by his wife, two daughters, stepson, stepdaughter, two brothers, four sisters, and his dog, Poppy, according to his family’s Facebook message.

This story was originally featured on Fortune.com