algebraic3d

solid box = orthobrick (-3, -3, -3; 3, 3, 3)  -bc=1;
solid electrod1 = orthobrick (0.2, -0.5, -0.5; 0.3, 0.5, 0.5) -bc=2;
solid electrod2 = orthobrick (-0.3, -0.501, -0.501; -0.2, 0.501, 0.501) -bc=3;

solid air = box and not electrod1 and not electrod2;


tlo air;