Fastener

Abstract

The first fastener comprises a post, a fifth outer boss, an outer slab, a first hole and a second inner flange. The fifth outer boss is provided in an upper portion of the post. The outer slab perpendicular to the post is provided in a lower portion of the post. The first hole is provided within a local region of the outer slab below the post. The second inner flange is provided on an inner wall of the first hole. The second inner flange has a first gap greater than a width of the fifth outer boss. The upper surface of the second inner flange is used for abutting on a lower surface of a fifth outer boss of a second fastener having a same structure as the first fastener when limiting a position of connected pieces in a height direction of the post. Two sections of the second inner flange and two sections of the first gap are provided on the inner wall of the first hole in a staggered manner. Each section of the second inner flange is equivalent to ¼ of a circumference of the inner wall of the first hole. Each section of the first gap is equivalent to ¼ of the circumference of the inner wall of the first hole.