Yale's secret society buildings (some of which are called "tombs") were built both to be private yet unmistakable. A diversity of architectural styles is represented: Berzelius, Donn Barber in an austere cube with classical detailing (erected in 1908 or 1910); Book and Snake, Louis R. Metcalfe in a Greek Ionic style (erected in 1901); Elihu, architect unknown but built in a Colonial style (constructed on an early 17th-century foundation although the building is from the 18th century); Mace and Chain, in a late colonial, early Victorian style (built in 1823). Interior moulding is said to have belonged to Benedict Arnold; Manuscript Society, King Lui-Wu with Dan Kniley responsible for landscaping and Josef Albers for the brickwork intaglio mural. Building constructed in a mid-century modern style; Scroll and Key, Richard Morris Hunt in a Moorish- or Islamic-inspired Beaux-Arts style (erected 1869–70); Skull and Bones, possibly Alexander Jackson Davis or Henry Austin in an Egypto-Doric style utilizing Brownstone (in 1856 the first wing was completed, in 1903 the second wing, 1911 the Neo-Gothic towers in rear garden were completed); St. Elmo, (former tomb) Kenneth M. Murchison, 1912, designs inspired by Elizabethan manor. Current location, brick colonial; Shabtai, 1882, the Anderson Mansion built in the Second Empire architectural style; and Wolf's Head, Bertram Grosvenor Goodhue (erected 1923-4).

What is another term for some of Yale's secret society buildings?