Laser warning lights

while true do
	if redstone.getInput("top") == false then
	redstone.setOutput("bottom", false)
	while redstone.getInput("top") == false do
		redstone.setOutput("left", true)
		redstone.setOutput("right", false)
		sleep(1)
		redstone.setOutput("left", false)
		redstone.setOutput("right", true)
		sleep(1)
	end
	else
	redstone.setOutput("left", false)
	redstone.setOutput("right", false)
	redstone.setOutput("bottom", true)
	sleep(1)
	end
end