As noted with the function description, the diamond is centered at the origin and has a width and height of 2. We want to scale down the size of the diamond and then move it to its location inside the projection window. We recall from the tutorial on 2D transformations, the last transformation called is the first to be applied to the geometry. Therefore, the order of operations is scale followed by translate and, in turn, the calls are in the order glTranslated followed by glScaled. The parameters used in the calls to glScaled and glTranslated reduce the width and height of the diamond to 0.2 and then places its center at (0.2, 0.8). Thus, this first instance of a diamond is 0.1 units from the left and top projection window boundaries.