The forms of the columns and capitals vary somewhat between different buildings. Generally the capitals are carved with two heavily decorated back-to-back animals projecting out from the column. These function as brackets to support the architrave or roof timbers, while the flat backs of the animals support timbers running at right angles (see the reconstruction in the Louvre below). As they project the animals may be called protomes. The bull is the most common animal, but there are also lions, bulls with the head of a man in the style of the Assyrian lamassu, and griffins with the heads of eagles and the bodies of lions.