function layer_1() {
	L1.style.visibility = "visible";
	L2.style.visibility = "hidden";
	L3.style.visibility = "hidden";
	L4.style.visibility = "hidden";
	L5.style.visibility = "hidden";
	L6.style.visibility = "hidden";
}
function layer_2() {
	L1.style.visibility = "hidden";
	L2.style.visibility = "visible";
	L3.style.visibility = "hidden";
	L4.style.visibility = "hidden";
	L5.style.visibility = "hidden";
	L6.style.visibility = "hidden";
}
function layer_3() {
	L1.style.visibility = "hidden";
	L2.style.visibility = "hidden";
	L3.style.visibility = "visible";
	L4.style.visibility = "hidden";
	L5.style.visibility = "hidden";
	L6.style.visibility = "hidden";
}
function layer_4() {
	L1.style.visibility = "hidden";
	L2.style.visibility = "hidden";
	L3.style.visibility = "hidden";
	L4.style.visibility = "visible";
	L5.style.visibility = "hidden";
	L6.style.visibility = "hidden";
}
function layer_5() {
	L1.style.visibility = "hidden";
	L2.style.visibility = "hidden";
	L3.style.visibility = "hidden";
	L4.style.visibility = "hidden";
	L5.style.visibility = "visible";
	L6.style.visibility = "hidden";
}
function layer_6() {
	L1.style.visibility = "hidden";
	L2.style.visibility = "hidden";
	L3.style.visibility = "hidden";
	L4.style.visibility = "hidden";
	L5.style.visibility = "hidden";
	L6.style.visibility = "visible";
}