snad

SIDES = { "left", "right" }

print("Snadding...")
while true do
    for i,s in ipairs(SIDES) do
        redstone.setOutput(s, true)
    end
    os.sleep(0.2)
    for i,s in ipairs(SIDES) do
        redstone.setOutput(s, false)
    end
    os.sleep(0.2)
end