4K (computer virus)
4k is a computer virus which infects COM files and EXE files. The virus was one of the first to employ stealth tactics. Infected systems will hang, after September 22 every year, which is also the date of birth Bilbo Baggins, a character from "The Lord of the Rings". The code was intended to display the message "Frodo Lives", but hangs in all known variants.
4DX
4DX is a motion picture technology owned and developed by South Korean company CJ 4DPLEX, a part of the CJ Group. 4DX allows a motion picture presentation to be augmented with environmental effects such as seat motion, wind, rain, lights, and scents along with the standard video and audio. As such, theaters must be specially designed for and equipped with 4DX technology. The experience was introduced commercially in 2009 with the release of "Journey to the Center of the Earth" in Seoul, South Korea.