module step(len, mod)
{
	for (i = [0:$children-1])
		translate([ len*(i - ($children-1)/2), 0, 0 ]) children((i+mod) % $children);
}

for (i = [1:4])
{
	translate([0, -250+i*100, 0]) step(100, i)
	{
		sphere(30);
		cube(60, true);
		cylinder(r = 30, h = 50, center = true);
	
		union() {
			cube(45, true);
			rotate([45, 0, 0]) cube(50, true);
			rotate([0, 45, 0]) cube(50, true);
			rotate([0, 0, 45]) cube(50, true);
		}
	}
}