Image: VIVID Gallery
I have always loved the look (and admired the skill involved) of wood which has been joined together without the use of nails.  While in the past,  joinery was all made by hand and so out of necessity joints were simple, electronic calibration and precision machinery now make it possible to create more complex joints quickly and accurately.

Take the desk made from mahogany above which was completely made with a CNC router.  Commissioned by Ontwerpduo and is distributed by VIVID Gallery, the piece is designed to show the intricate joinery thereby making it a design element.