Navigation Lights: The Blinking Lights on Plane Wings

I built a nightlight for my son's room in the shape of an airplane, and I wanted to make it as realistic as possible.

Ever notice the blinking lights on the tip of the wings of planes?

These are navigation lights. Green on the right wing, red on the left.

They're used so others can infer the orientation of a craft. If you see the lights of an airplane, and the green light is on the left, then you know it's moving toward you. If it's on the right, it's moving away from you.

It's a very simple system, and in case of emergency, say your radar is broken, you can use these lights to determine if a craft is coming toward you or moving away.

And navigation lights are not only used by planes, also used on boats and even spacecraft, such as the SpaceX Dragon capsule.