group() {
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 3], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 6], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 0, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 9], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 1], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 12], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [1, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
	multmatrix([[1, 0, 0, 0], [0, 1, 0, 15], [0, 0, 1, 0], [0, 0, 0, 1]]) {
		group() {
			multmatrix([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 4], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
					multmatrix([[1, 0, 0, -1], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = true);
					}
				}
			}
			multmatrix([[1, 0, 0, 8], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					multmatrix([[1, 0, 0, 0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
					multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
						square(size = [1, 1], center = false);
					}
				}
			}
			multmatrix([[1, 0, 0, 12], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
				linear_extrude(height = 3, center = false, convexity = 1, twist = 180, slices = 20, scale = [0, 0], $fn = 0, $fa = 12, $fs = 2) {
					difference() {
						square(size = [2, 2], center = true);
						multmatrix([[1, 0, 0, -0.5], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]) {
							square(size = [1, 1], center = true);
						}
					}
				}
			}
		}
	}
}