For a major retrospective of Dutch furniture designer and architect Gerrit Rietveld, the team at Studio Wieki Somers collaborated with chocolatier Rafael Mutter to create Chocolate Mill. The piece was comprised of a giant cylindrical chocolate block that was carefully organized in 10 stacked layers, with flavored shapes used to create different geometric patterns. As a crank-turned blade similar to a cheese slicer grazed shavings off the top, the hidden layers were slowly revealed. You can watch a timelapse of the piece in the video above. (via Designboom, Design You Trust)
Update: A little bit more background in this video from Robert Andriessen.