Designed on Christmas Day 2012, here is the second of my series of printable interlocking puzzles, and this time it's a 4x4x4 cube. 'Printable' means no support material required. 'Interlocking' means the puzzle pieces fit together only in the correct sequence and will not fall apart when the puzzle is moved. This puzzle is much more challenging than PIP#1 so I will be happy to provide a solution on request, if you need it. Update: The solution video is at http://www.youtube.com/watch?v=oNIwRid7390I have uploaded the six pieces individually to allow each piece to be printed a different colour, but have also provided an STL file with all six pieces arranged together for convenience.If you want to print the puzzle in PLA you will need a fan to prevent the tallest piece from melting. You will need a well tuned printer to ensure that you get a nice snug fit when you assemble the puzzle. I used Slic3r with settings of 0.2 mm layer height, 0.4 mm extrusion width and 40% infill at 30 mm/s.