Read this article: http://www.penguin2.com/link-pyramid/.. After reading this blog, You will know all about link pyramid
also this: http://www.jonathanleger.com/build-a-link-pyramid-to-rank-your-sites-in-google/ it's a bit old but you'll get the basics
@Lost Symbol I hope you can Google it out Just open the Google and write link pyramid they very first result that comes is enough to provide quality information about the link pyramid like for your ease @smithrick has mentioned in the comment box. I'll say rather than thinking asking such question here I would say first try googling it out.
Link pyramid same as link wheel. check this Image you will see how it works, and how to use. read this article :http://www.penguin2.com/link-pyramid/