What is the splayed crack in the wall? Why do you call it

Eight-shaped cracks, usually in the longitudinal direction of the house, at the top or bottom of the house at both ends, or through one or two floors, are symmetrical and oblique cracks, and the appearance is "eight-shaped" or inverted "eight-shaped", which are all called eight-shaped cracks. Its key words are: the two ends of the house are obliquely symmetrical. Generally, it is common in brick-concrete structure, which is mostly formed by uneven settlement of foundation. Horizontal crack refers to the cracks formed in the wall of a building along the horizontal direction. Horizontal cracks are mostly caused by temperature stress damage. In exterior walls, it is common at the junction of different materials. Such as: the joint of concrete beam or concrete floor (house) cover and brick wall. Its shape is a horizontal straight line. It is in a "one" shape.