FIGURE 10.

Comparison between three body interaction energy if energy were pair-additive (w(2)(2R) + 2w(2)(r), dashed line) and actual result (w(3)(r), solid line). Inclusions are configured as shown: two inclusions are separated by the minimum spacing and a third is brought toward the dimer while being kept equidistant from each of the other inclusion centers. The solid line does not extend to minimum separation because an equilateral triangle with sides of length 2R is not possible on our square lattice. All parameters are the same as those used for the solid line in Fig. 8.