Embedded codes are blue screens of code that can be seen from Machine Point of View (MPOV), disrupting the flow of data. Over the course of the second half of season two, the number and frequency of the code screen disruptions increased, suggesting degraded functioning of some type by the Machine.

The codes first appeared in the episode “One Percent”, following the upload of viral software into the internet by Kara Stanton. (“Dead Reckoning”) Over time, we learned that the virus was developed by Decima Technologies, whose representative, Greer, recruited Stanton. Once Stanton's mission was complete, Greer monitored the virus for the arrival of its zero day, when it would become active. As he did, Finch monitored the virus, having determined its target was the Machine, unable to do anything to stop it. At the time, it was unclear whether the blue screens were part of the virus's activity or the consequence of it.

Contents show]

The Codes by Episode

Below is a list of code screens by episodes in which they appear. Each screen directs the Machine to a particular piece of text, all available online. For detailed information about the meaning of each code, visit the individual articles of codes by episode (also listed below).

Main article: One Percent/Embedded codes

Lady Macbeth's sleepwalking scene famously portrays her as a soul in torment, unable to rid herself of the guilt she feels at having pushed her husband to commit murder.

Main article: Booked Solid/Embedded codes

The Book of Revelation describes the end of the world. In Chapter 16, seven angels with bowls are announced, each bowl pouring forth a plague upon the earth.

Main article: Relevance/Embedded codes

Conrad's "Heart of Darkness" is a novella about the collision between the so-called civilized and savage worlds at the height of the colonial period, and how a supposedly civilized man can become a savage. It was adapted as the 1977 Vietnam era film Apocalypse Now .

. The Voynich Manuscript is an untranslated, putative 15th century Italian book believed to be a manual of plants and their medicinal qualities. The book has defied translation by experts, including WWII codebreakers, and some theorize it may be a fraud. Named for its 1912 purchaser, it is currently held in the rare book collection at Yale University.

Main article: Proteus/Embedded codes

Main article: All In/Embedded codes

Dante's Inferno describes the journey through the nine circles of Hell. Canto XXXII describes part of the ninth circle, where traitors commit acts of treachery.

Cinderella is a well-known fairy tale with thematic elements including rising to attention after time in obscurity, and oppression of the disadvantaged by the advantage. Fairy tales are small morality tales designed to teach children life lessons, often by frightening them. The Grimm Brothers' fairy tales are known for including more graphic elements than other versions. In the excerpt, one of the step-sisters is being encouraged to cut off her toes to make the slipper fit.

Main article: Trojan Horse/Embedded codes

Main article: In Extremis/Embedded codes

Main article: Zero Day/Embedded codes

Origin and Purpose

Although the codes began appearing after Decima Technologies uploaded a virus, the virus itself originated on the Ordos laptop. The Decima virus was designed activate a routine in five months that would shut down the Machine (shown by red error screens), reboot and seeks its administrator by calling a specified public telephone. 184 seconds after shut-down, the Machine would reboot and call a designated phone number, allowing administrator access for 24 hours to whomever answered the public telephone the Machine called. It was Decima's plan to cover every public telephone on the streets of New York, thereby gaining administrator access for its own aims.

Unknown to Decima, the main virus also contained a second, hidden routine, designed by Finch to teach the Machine how to protect itself before the first virus activated. Each blue code screen was a lesson in threat or self-preservation. The images contained coded information about concealment techniques, codebreaking, counter-terrorism, the flaws of humanity (war, genocide, slavery), and the problems with reaching for godhood (the story of Babylon). It was Finch's intention that the Machine would learn how to protect itself when it was under threat, and to move itself to a new location. The five-month delay gave the machine time to slowly make the move to a new hidden location.

Harold Finch stated he designed this hidden program to free the machine of malicious human control. The full meaning and extent of this freedom is not yet known. In the end, what appeared to be an attempt at sabotage by Finch turned out to be a fail-safe device designed to protect the Machine from outside interference.

Notes