Ciphers.
Bill's Cipher

This is Bill Cipher's Cipher. It is used when communicating with Bill, and other Audience Members. Bill Cipher himself created this Cipher when encoding messages for humans to find, and they are hidden throughout the World.
Author's Symbol Subsitution Cipher

This is "The Author's" Symbol Subsitution Cipher. Standford Pines (Ford, Fordsy, Sixer, Pointdexter) Created this Cipher to encode the messages hidden within his research journals.
Audience Cipher

This is used to identify other Audience Members, and to communicate. Somewhat like Cipher's Cipher 2.0, though both are still used and Audience Cipher is still under revision.
Grand Unified Theory Of Weirdness
The Grand Unified Theory of Weirdness is a scientific term coined by Dr. Stanford Pines to describe certain places like Gravity Falls (also known as weirdness magnets) with many paranormal and unexplained scenarios. Though his research never amounted to much (in the public eye, at least) This theory was created with Dr. Pines, Dr. Fiddleford McGucket, and of course, Bill Cipher.
This theory speculates that there is a rip between dimensions somewhere in Gravity Falls, so this is the creatures' new home. Later proven to be false, the theory then just states that places like Gravity falls are a weirdness magnet. In a jellybean analogy (Journal 3) Ford explains that though jellybeans are all made out of the same material, and have different flavor, coating, and color, some odd ones are bound to come out. When rolled down a hill at the border of Gravity Falls, the strangely-shaped beans appeared to roll up the hill? This revised verion is known as "The True Theory of Weirdness".
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