Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, cars, motorcycles, and bicycles.
Pietra dura (Italian: [ËpjÉËtra ËduËra]) or pietre dure [ËpjÉËtre ËduËre] (see below), called parchin kari or parchinkari in South Asia, is a term for the inlay technique of using cut and fitted, highly polished colored stones to create images. It is considered a decorative art.
Triquetra (/traÉªËkwÉtrÉ/ ; Latin tri- three and quetrus cornered) originally meant  triangle  and was used to refer to various three-cornered shapes.he triquetra has been found on runestones in Northern Europe and on early Germanic coins. It presumably had pagan religious meaning and it bears a resemblance to the Valknut, a symbol associated with Odin.