A building system includes blocks having first and second side surfaces that are perpendicular to a common plane defining a subtended angle, couplers and receivers are defined in the first and second side surfaces such that chains of blocks may be coupled to one another in rows forming closed loops or non-closed chains. Rows may be coupled together by engaging core links with a block in each row and with a core rod passing through each row. Blocks in each row may include a peg and aperture engaging a corresponding aperture and peg in adjacent rows to facilitate alignment. Core rods threadably secure to other cord rods, slanted blocks, caps, and other feature blocks in order to capture a stack of rows in engagement with the core rods. Blocks including decorative features and forming parts of pivoting joints may also be included within a row.