Not Commercial In media TTP: a technology project in the Dilbert comic strip. The initials stand for "The TTP Project". GRUNGE: defined by Homer Simpson in The Simpsons episode That '90s Show as "Guitar Rock Utilizing Nihilist Grunge Energy", another uncommon example of a recursive acronym whose recursive letter is neither the first nor the last letter. BOB: the primary antagonist from the series Twin Peaks. His name itself is an acronym standing for "Beware of BOB". KOS-MOS: a character from the Xenosaga series of video games. "KOS-MOS" is a recursive acronym meaning "Kosmos Obey Strategical Multiple Operating Systems". Hiroshi Yoshimura's "A・I・R" stands for "AIR IN RESORT". Mutually recursive or otherwise special The GNU Hurd project is named with a mutually recursive acronym: "Hurd" stands for "Hird of Unix-Replacing Daemons", and "Hird" stands for "Hurd of Interfaces Representing Depth." RPM, PHP, XBMC and YAML were originally conventional acronyms which were later redefined recursively. They are examples of, or may be referred to as, backronymization, where the official meaning of an acronym is changed. Jini claims the distinction of being the first recursive anti-acronym: 'Jini Is Not Initials'. It might, however, be more properly termed an anti-backronym because the term "Jini" never stood for anything in the first place. The more recent "XNA", on the other hand, was deliberately designed that way. Most recursive acronyms are recursive on the first letter, which is therefore an arbitrary choice, often selected for reasons of humour, ease of pronunciation, or consistency with an earlier acronym that used the same letters for different words, such as PHP, which now stands for "PHP: Hypertext Preprocessor", but was originally "Personal Home Page". However YOPY, "Your own personal YOPY" is recursive on the last letter. A joke implying that the middle initial "B." in the name of Benoit B. Mandelbrot stands for "Benoit B. Mandelbrot" plays on the idea that fractals, which Mandelbrot studied, repeat themselves at smaller and smaller scales when examined closely. Other According to Hayyim Vital, a 16th–17th century kabbalist, the Hebrew word adam (אדם, meaning "man") is an acronym for adam, dibbur, maaseh (man, speech, deed). According to Isaac Luria, a 16th century kabbalist, the Hebrew word tzitzit (ציצת in its Biblical spelling, meaning "ritual fringes") is an acronym for tzaddik yafrid tzitziyotav tamid ("a righteous person should separate [the strings of] his tzitzit constantly"). See also (Redundant Acronym Syndrome syndrome) TLA, the three-letter