When you think of an Easter egg hunt, you may think of tracking down chocolate eggs.

In computer software and media, an Easter egg is an intentional inside joke, hidden message or image, or secret feature of work.

The name is used to evoke the idea of a traditional Easter egg hunt in which viewers hunt out the secret just like they would the chocolatey treat.

The term was coined to describe a hidden message in the Atari video game Adventure that encouraged the player to find further hidden messages in later games, leading them on a ‘hunt’.

At the time, Atari did not include programmers’ names in the game credits, fearing that competitors would attempt to steal their employees.

Employee Warren Robinett, who disagreed with his supervisor over this lack of acknowledgment, secretly inserted the message ‘Created by Warren Robinett’ that would only appear if a player moved his/her avatar over a specific pixel during a certain part of the game.

When Robinett left Atari, he did not inform the company of the acknowledgment that he included in the game. Shortly after his departure, his message was exposed by a player who told Atari about his discovery.

Atari’s management initially wanted to remove the message and release the game again, but this was deemed too costly an effort. Instead, Steve Wright, the Director of Software Development in the Atari Consumer Division, suggested that they keep the message and, in fact, encourage the inclusion of such messages in future games, describing them as Easter eggs for consumers to find.

The first text adventure game, Colossal Cave Adventure, from which Adventure was fashioned, included several secret words. One of these was ‘xyzzy’, a command which enabled the player to move between two points in the game world.

Since Adventure, there has been a long history of video game developers placing Easter eggs in their games. Most Easter eggs are intentional – an attempt to communicate with the player or a way of getting even with management for a slight.

Easter eggs in video games have taken a variety of forms, from purely ornamental screens to aesthetic enhancements that change some element of the game during play. More elaborate Easter eggs include secret levels and developers’ rooms – fully functional, hidden areas of the game.

Other Easter eggs originated unintentionally. The Konami Code, a type of cheat code, became an intentional Easter egg in most games but originated from Konami’s Gradius for the Nintendo Entertainment System. The programmer, Kazuhisa Hashimoto, created the code as a means to rapidly debug the game by giving the player’s avatar additional health and powers to easily traverse the game.

In computer software, Easter eggs are secret responses that occur as a result of an undocumented set of commands. The results can vary from a simple printed message or image to a page of programmer credits or a small video game hidden inside an otherwise serious piece of software.

In the TOPS-10 operating system, the make command is used to invoke the TECO editor to create a file. If given the filename argument love, so that the command reads make love, it will pause and respond ‘not war?’ before creating the file.

The Google search engine famously contains many Easter eggs, given to the user in response to certain search queries. For example, Google Maps once responded to a request for directions from New York City to Tokyo by telling the user to kayak across the Pacific Ocean.

Steve Jobs banned Easter eggs from Apple products upon his return to the company.

The first Easter egg to appear after his death was in a 2012 update to the Mac App Store for OS X Mountain Lion, in which downloaded apps were temporarily timestamped as January 24, 1984, the date of the sales launch of the original Macintosh.

Since then, Easter eggs have become more and more common and can be found not only in games, but productivity software, online services, and even hardware.

While computer-related Easter eggs are often found in software, occasionally they exist in hardware or firmware of certain devices. On some home computers, the BIOS ROM contains Easter eggs.

An errant 1993 AMI BIOS on November 13, 1993, proceeded to play Happy Birthday via the PC speaker repeatedly instead of booting, as well as several early Apple Macintosh models that had pictures of the development team in the ROM.

So next time you boot up your favourite game or sit down to do some work at your laptop, see if you can find any hidden secrets you’ve never seen before.

Happy hunting!