Abstract: An asymmetrical interlocking universal construction element with a unique polygonal shape. It allows for constructing flat surfaces, internal corner, and external corner surfaces from a set consisting essentially of the same construction elements. It can be used to finish edges of an opening in a flat surface (e.g., for a door or window). Construction elements can be cut to size on-site. Assembly of two or more construction elements allows insertion of an S-shaped thin-walled metal element to provide load bearing capability. Application of the elements in construction assembly may use any raw material as long as it is shape-stable (i.e., capable of carrying its own weight only). The construction elements may be hollow or solid throughout.