for (int zs = 0; zs < len; ++zs) {
for (int x = 0; x < width; ++x) {
for (int y = 0; y < height; ++y) {
final BaseBlock block1 = data[x][y][zs];
if (block1 != null) {
block1.flip(dir);
}
// Skip the center plane
if (zs == length - zs - 1) {
continue;