As we learned at Holz-Handwerk, Germanic tradespeople who are formally trained are required to produce an original "masterpiece" in order to obtain guild membership. (This is something like a dissertation for a doctoral candidate.) Masterpieces don't necessarily have to be practical constructions, but are seen as demonstrations of skill in both design and execution.
Vienna-based craftsman Vinzenz Hefele's masterpiece from 1840, which took a year and a half to construct, is an insanely over-the-top piece of furniture. Called the Biedermeier secretary, this desk contains 105 drawers, most of them concealed and accessed through clever and complicated low-tech mechanisms. It's part of the collection of MAK (The Museum of Applied Arts) in Vienna, and MAK restorer Johannes Ranacher has both restored the piece and learned how each and every part works.
Here Ranacher gives a demonstration of the desk, showing you not only how this or that compartment works, but also how it's "powered." It's mind-blowing that someone designed this with a pencil and paper, then built this thing by hand: