An ogee (/oʊˈdʒiː/ /ˈoʊdʒiː/) is the name given to objects, elements, and curves—often seen in architecture and building trades—that have been variously described as serpentine-, extended S-,[1]:218 or sigmoid-shaped.[citation needed] Ogees consist of a "double curve", the combination of two semicircular curves or arcs that, as a result of a point of inflection[citation needed] from concave to convex or vice versa,[1]:218 have ends of the overall curve that point in opposite directions (and have tangents that are approximately parallel).[citation needed]