A building block and a set of modular building elements is intended for construction of foundational and wall structures. The building block comprises a plurality of outer walls, a cavity, at least one inner wall, and at least two connecting elements. The outer walls are arranged in an n-gon shape surrounding the cavity and the cavity is open on both lower and upper sides. The cavity is divided by the inner wall into at least two parts. At least one part is adapted for the insertion of an insulating insert. Each connecting element is adapted for insertion into the cavity. The first connecting element is intended for insertion into the cavity of a different one of two neighbouring building blocks of a different row than the second connecting element. Each connecting element is attached to a wall of the building block and offset from that wall in a direction towards the inside of the cavity. Each connecting element comprises a wall of the connecting element protruding from a respective wall of the building block. The wall of the connecting element comprises a free end and side edges. The side edges approach each other from a place of attachment to the wall towards the free end. An insulating layer at least partially surrounds a part of the cavity adapted for the insertion of the insulating insert. The set of modular building elements comprises foundation building blocks comprising the cavity enclosed by the solid bottom and hollow building blocks.

A retaining wall block having a false joint and a system of retaining wall blocks. The retaining wall block includes a body having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can have a depth divided by the width greater than two inches. The false joint can have an interior angle of less than ten degrees. The system includes a plurality of retaining wall blocks and a first course of retaining wall blocks engaged with a second course of retaining wall blocks below. Each block in the system comprising a front face having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can extend a predetermined depth of a third surface.

A retaining wall block having a false joint and a system of retaining wall blocks. The retaining wall block includes a body having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can have a depth divided by the width greater than two inches. The false joint can have an interior angle of less than ten degrees. The system includes a plurality of retaining wall blocks and a first course of retaining wall blocks engaged with a second course of retaining wall blocks below. Each block in the system comprising a front face having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can extend a predetermined depth of a third surface.

A semi-interlocking construction block system may include blocks having prism shaped male and female fittings configured for semi-interlocking interaction. When mated the male and female fittings may engage along their respective interfacing upper bases and lower ends of their respective lateral side faces. Gaps may be defined between upper ends of their respective lateral side faces. The fittings may include arcuate edges which may be quarter rounded.

A retaining wall block having a false joint and a system of retaining wall blocks. The retaining wall block includes a body having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can have a depth divided by the width greater than two inches. The false joint can have an interior angle of less than ten degrees. The system includes a plurality of retaining wall blocks and a first course of retaining wall blocks engaged with a second course of retaining wall blocks below. Each block in the system comprising a front face having a first textured surface and a second textured surface and a false joint dividing the first and second textured surface. The false joint can extend a predetermined depth of a third surface.