h_matrix = [ [1.0, 0.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0] ] positions = [ [0.0, 0.0, 0.0], [0.5, 0.5, 0.0], [0.5, 0.0, 0.5], [0.0, 0.5, 0.5] ]https://www.saylor.org/content/cubic_neighbors/cubic_near_neighbors.html