group() {
	difference() {
		sphere($fn = 0, $fa = 12, $fs = 2, r = 20);
		multmatrix([[1, 0, 0, -2.92], [0, 1, 0, 0.5], [0, 0, 1, 20], [0, 0, 0, 1]]) {
			multmatrix([[-1, 0, 0, 0], [0, 1, 0, 0], [0, 0, -1, 0], [0, 0, 0, 1]]) {
				import(file = "example012.stl", layer = "", origin = [0, 0], scale = 1, convexity = 5, $fn = 0, $fa = 12, $fs = 2);
			}
		}
	}
}