Bricks with grooves generally collect water, so they are generally flat bricks. Brick is a man-made small block for building, which is divided into sintered brick (mainly clay brick) and non-sintered brick (lime sand brick, fly ash brick, etc.), commonly known as brick. Clay brick is made of clay (including shale, coal gangue and other powder) as the main raw material, which is processed by mud, shaped, dried and roasted. In the Spring and Autumn Period and the Warring States Period, China successively created square and long bricks. In the Qin and Han Dynasties, brick-making technology, production scale, quality and fancy varieties all developed significantly, and the world called it "Qin Brick and Han Tile".