This is the second version of my half proportional 2x2x4. It features a few tweaks which make assembling / finishing the puzzle a little easier.
Print:1 x core8 x inner corner8 x outer corner9 x inner edge3 x inner center3x bandaged inner center
Requires six M3 Screws and three springs. Cut the springs in half and put half a spring on each side of the puzzle.