Can anyone explain the Intracoastal Waterway (ICW) buoyage system?

an easy way to use the triangles and squares is: Think of the squares as flat like the beach, keep them to beach or ocean side, think of triangles as like mountains and keep them to the landm side. It is crude and simple but works. Most importantly keep your chart and tide tables handy, monitor the vhf for traffic, weather and safety broadcast, watch out for oncoming and ping traffic, be careful of manatees and dolphins, watch for debris, crabtraps, read your guidebooks, and by the way, relax and enjoy the trip. The ICW is a very nice trip if you do not let a schedule ruin your fun.