Animated diagram of lights used on <a href="https://en.wikipedia.org/wiki/Cardinal_mark" class="extiw" title="w:Cardinal mark">cardinal marks</a> as seen at night.  These lights are in the "quick" configuration.
<a href="//commons.wikimedia.org/wiki/User:Denelson83" title="User:Denelson83">Denelson83</a>
<span class="int-own-work" lang="en">Own work</span>