Okie's got it right. Glue 2 pieces of wood together and then bend them into a shape while the glue is still wet or unset and the glue holds it in the shape.
As for that being the best design...
It's more of a technique than a design. It's great but there is a lot more to being the "best". Remember that the TBB series is written by many different authors. So one of them has a drastically different opinion of the best design. As does everyone reading this