Block[{a, b, c, n, p, r},
a = {3, 0, 0} ;
b = {0, 3, 0} ;
c = 1.5{1, 1,1} ;
n = 2 ;
r = 0.9 ;

p= Flatten[
Table[ {Hue[0.5 + k/6], Sphere[i a + j b + k c, r]}, {i, 0, n}, {j, 0, n}, {k, 0, n} ]
, 3] ;

{ScalarTripleProduct[a, b, c], Graphics3D[ p ] }
]