Abstract: An arcuate building structure containing at least three five-sided building blocks, at least three six-sided building blocks, and means for connecting one of said five-sided building blocks to at least one of said six-sided building blocks. The top side of the six-sided block has a substantially triangular shape, and is substantially parallel to the bottom side of the six-sided block. The front side of the six-sided block has a substantially trapezoidal shape with a top edge, a bottom edge, a right edge, and a left edge. The right edge and the left edge have equal lengths and form equal angles with the bottom edge. The back side of the six-sided block has a substantially triangular shape with at least two sides equal in length to each other. The left and right sides of the six-sided block are congruent with each other, are in the shape of a parallelogram, and contain a recess within their borders.