This lighthouse operates by showing and hiding a glowstone block using a piston which is powered by a clock set to 1 second from the base! All wires are hidden and the appearance is quite unique!

If you would like me to upload the schematic please post a comment requesting it!

The pictures are dark but if you click to enlarge they show quite nicely and i assure you that you will be able to see this at night as far as your computer can load terrain!