What are stone quoins?

Stone quoins are L shaped stone pieces that are typically used to protect the corners of brick and stone houses. They can measure to be square or staggered depending on the style that you like. They were initially used on Georgian style houses but have now been adapted to any style house. They come in different styles, such as wood core, polystyrene core, or stone. With stone being the best option out of all three followed by polystyrene due to its lifetime and flexibility.