zhè / tiáo / tū / zhé / xiàn / yóu / jǐ / gè / xiàng / wài / tū / chū / de / xiàn / duàn / lián / jiē / ér / chéng这条凸折线由几个向外凸出的线段连接而成。This convex polygonal line is made up of several outward-curving segments.