Abstract: A spacer for use in forming a wall of glass blocks which includes a pair of parallel elongated first arms, a pair of parallel elongated second arms, with each of the second arms being perpendicular to a corresponding one of the first arms so as to form a pair of spaced apart crossed arms. An elongated connecting bar interconnects to the crossed arms a plate positioned parallel to each of said crossed arms. A frangible coupling affixes each of the plates to a corresponding one of the crossed arms and an elongated vane element extends out from and across the plates and passes through a notional line through a center of each of the frangible couplings so that a user may grip and twist the vane element so as to impart a torque about the notional line which shears an associated frangible coupling at its joint with an associated one of the crossed arms without imparting any translational force to the spacer.