How old is Tetris, really?

Until a certain point in the late 2000s, Tetris would have officially been 39 years old this year. But now it's 40 years old, according to the attendant celebrations, promotions and earned media. What's the deal? Time Extension's Damien McFerran investigates and finds the temporal anomaly occured in 2009.

The first person to notice this odd rewriting of history seems to be Necrosaro, who, on 24th September, 2014, posted a forum topic concerning the "revised" release date of June 6th, 1984 – the same date cited by many publications when it came to celebrating the game's 40th anniversary earlier this month. … [but] an overwhelming amount of evidence suggests that the game wasn't officially published in 1984 and wasn't even in a playable state until 1985 (in this 1993 interview, Pajitnov himself says he "believes" the game was completed in '85). Sure, Pajitnov began creating the game in 1984 – but anniversaries are traditionally attributed to release dates, not the date at which development began.

Cynically, you'd put it down to marketing shenanigans at the Tetris Company. But given Tetris's conceptual simplicity and its emergence from Soviet academia and all its dismalities, it seems fair to give Pajitnov credit for when he started work on it, to the tetrominous eureka moment it all sprang from. Wikipedia:

In 1984, while trying to recreate a favorite puzzle game from his childhood featuring pentominoes, Pajitnov imagined a game consisting of a descent of random pieces that the player would turn to fill rows. Pajitnov felt that the game would be needlessly complicated with twelve different shape variations, so he scaled the concept down to tetrominoes, of which there are seven variants. Pajitnov titled the game Tetris, a word created from a combination of "tetra" (meaning "four") and his favorite sport, "tennis".

Because the Electronika 60 had no graphical interface, Pajitnov modelled the field and pieces using spaces and brackets (45 lines of 80 ASCII characters). Realizing that completed lines filled the screen quickly, Pajitnov decided to delete them, creating a key part of Tetris gameplay. This early version of Tetris had no scoring system and no levels, but its addictive quality distinguished it from the other puzzle games Pajitnov had created. Pajitnov wrote the game using Pascal for the RT-11 operating system on the Electronika 60.

Pajitnov had completed the first playable version of Tetris c. 1985

Here's the trailer to the recent movie about Tetris, starring Taron Egerton and Nikita Yefremov. It's perhaps the most exciting movie of all time about negotiating a multilateral stakeholder engagement process to resolve intellectual proprerty misalignments, i.e. convincing the Soviets to make some actual damned money from something.