Redstone mob spawner

local receiving_signal

While true do

	if redstone.getInput("left") then
	 receiving_signal = true
	elseif redstone.getInput("right") then
	 receiving_signal = true
	elseif redstone.getInput("front") then
	 receiving_signal = true
	elseif redstone.getInput("back") then
	 receiving_signal = true
	else
	 receiving_signal = false
	end

	if receiving_signal == true then
		redstone.setOutput("top", true)
	else
		redstone.setOutput("top", false)
	end

end