Building blocks are an essential part of construction, and there are several different types. LEGOS are a popular type of building block made of plastic that can be used to construct models and toys. ADOBES are sun-dried mud bricks used in traditional architecture, particularly in the southwestern United States. BRICKS are a type of masonry unit made from clay or shale and are commonly used in modern construction. ABCS are the basic building blocks of language, and CORNERSTONES are figurative building blocks that refer to the fundamental principles of an organization or system.