Shou sugi ban, or Yakisugi, is a traditional Japanese method of burning cedar (sugi) before finishing it with natural oil. Normally used as exterior siding, the charred wood is pest and rot resistant for up to eighty years.
This bookshelf was based off of the bilvet. You can watch a video of how to make a 3D bilvet here and how the designers built the bookshelf here. http://www.deceptology.com/2011/04/impossible-optical-illusion-bookshelf.html