the tree that bore them was cut down during renovations of the house in the 2005–2006 academic year. Attached to another tree was another wooden swing, but that was cut down in 2019. In another side of the courtyard is a couch swing. The letters of Blacker House are γδβγ (Greek letters for gdbg, or God damn Blacker gang). The story is that in 1978 or 1979, it was popular for Blacker students to climb on top of elevators and ride them. One time, security went inside the elevator looking for the students, who were on top of the elevator. The security muttered, "God damn Blacker gang", and the phrase stuck. Blacker students began signing GDBG or γδβγ on all their pranks. Blacker has also been referred to as the house of fucking geniuses and the inscription HOFG can be found throughout the tunnels along with γδβγ. In the 1960s the house slogan was "Blacker House for gracious living" which became "the house of gracious living" by the 1990s. Notable alumni include: William Shockley (1932) co-inventor of the transistor and Nobel laureate Walter Munk (1939) oceanographer who determined the reason for the moon's tidal locking with earth Carver Mead (1956) a key pioneer of modern microelectronics Kip Thorne (1962) Nobel Laureate and one of the world's leading experts on the astrophysical implications of Einstein's general theory of relativity, Richard P. Feynman Professor of Theoretical Physics, Emeritus at Caltech Michael Aschbacher (1966) an American mathematician best known for his work on finite groups Joseph Rhodes Jr. (1969, History) Pennsylvanian politician and activist Joseph Polchinski (1975) known for D-branes in string theory Zinovy Reichstein (1983, Mathematics) Mathematician, known for introducing the essential dimension Ian Agol (1992, Mathematics) Mathematician known for work in topology, professor at the University of California, Berkeley Doris Tsao (1997) – MacArthur Fellow, Neuroscientist, Professor of Biology at Caltech Po-Shen Loh (2004, Mathematics) Professor of Mathematics at Carnegie Mellon University, coach of USA International Math Olympiad team Dabney House Dabney House is the smallest of Caltech's houses. Members of Dabney House are referred to as Darbs, a combination of the name of the house with a 1920s slang term darb, meaning something or someone very handsome, valuable, attractive, or otherwise excellent. Joseph B. Dabney, owner of the Dabney Oil Syndicate, was a trustee of California Institute of Technology. Dabney Hall of the Humanities, a gift of Mr. and Mrs.