I changed my mind after handling a couple 3d printed prototypes. These look like traditional six piece burrs but are nothing like them. The angled internal geometry allows for some outrageous movements. They are very confusing and wonderfully different. This is the final three designs to complete the set. Construction was very challenging, requiring the creation of several new jigs and techniques.

"Go Back" is the fourth of the NOS designs and according to Greg is "One of my preferred of the series". A level 15 solution with four coordinate motion moves will have your head spinning!

Fit is very good, a little loose to account for dry conditions during the period in which it was made. This puzzle is delivered assembled.

60 copies made for sale, each signed and dated. This puzzle is shipped assembled.