In architecture, a dog-tooth or dogtooth pattern is an ornament found in the mouldings of medieval work of the commencement of the 12th century, which is thought to have been introduced by the Crusaders. The earliest example is found in the hall at Rabbath Ammon in Moab in Jordan (c. 614) built by the Sassanians, where it decorates the arch moulding of the blind arcades and the string courses. The pattern consists of four flower petals forming a square or diamond shape with central elements. The petals have the form of the pointed conical canine tooth, eye tooth or cuspid.