You’re probably no stranger to waves in the ocean. Little waves are fun to jump over on the shore, and the bigger ones can be a blast to surf on! But there are some waves that you really don’t ever want to encounter when you’re swimming in the ocean. Square waves look like a giant chess board over the ocean. It’s pretty awesome but incredibly dangerous. If you don’t get out of the water as soon as you see these things, your life could be at stake! So what are these things anyway, and where do they appear?