In the eighteenth century, the study of dome structures changed radically, with domes being considered as a composition of smaller elements, each subject to mathematical and mechanical laws and easier to analyse individually, rather than being considered as whole units unto themselves. Although never very popular in domestic settings, domes were used in a number of 18th century homes built in the Neo-Classical style. In the United States, most public buildings in the late 18th century were only distinguishable from private residences because they featured cupolas.