Here's one for the history books. Jordan Mechner, the veteran game designer responsible for Prince of Persia, has dug up a fan letter he received nearly 30 years ago from a 17-year-old called John Romero - the very same guy who'd go on to create FPS touchstones Wolfenstein, Doom and Quake at id Software.
Dated 25th March 1985, the letter, published in full on Kotaku, sees Romero praising 21-year-old Broderbund employee Mechner for his work on one-on-one fighter Karateka.
"I was absolutely stunned by the graphics, shadows and all," he gushed.
"You did a tremendous job and have, I think, defined the state-of-the-art for future Apple games. The technology has been in the Apple all along to do those graphics, it just needed a programmer like you to use it."
Romero then admitted that he was a budding programmer himself, before asking Mechner to impart some of his wisdom.
"How did you make the scrolling background? Ever since Choplifter I have been stumped on what kind of data drawing algorithm would be used to draw a scrolling background like yours," he wrote.
"If you decide to write back I would be eternally grateful if you explained this to me."
Elsewhere in the letter, the young Romero invites Mechner to check out a few of his own games.
"Many people feel that it is better than Lode Runner," he wrote, referring to an early effort called The Pyramids of Egypt.
"Anyway, ask me for it and it is yours. I'm currently trying to sell it to anyone I can (Broderbund is first on my list). My next game is going to be totally awesome. I can't wait until I get an idea for my next game!"
He signs off "John Romero, Disciple of the Great Jordan, and worshiper of the Magnificent Mechner".
Five years later, Romero would meet John Carmack while working at Softdisk. The pair, along with Adrian Carmack and Tom Hall, left the company a year later to set up id Software. Its seminal FPS Wolfenstein 3D would follow in 1992.
Mechner has been fairly quiet in recent years - his last game credit was on Prince of Persia: Sands of Time back in 2003.
Next Wednesday Romero and Mechner will share a stage together at the Game Developers Conference in San Francisco, along with Canabalt creator Adam Saltsman, Minecraft man Markus 'Notch' Persson and Epic Games boss Tim Sweeney, for a talk titled "Back to the Garage: The Return of Indie Development".
See below for some vintage Karateka footage.