Double-Hole Pin Cube II and III
Rick Eason Note that pieces A, B, D, E, F, and H are the same as for the Double-Hole Pin Cube (pieces C, G and I are missing from that set). Pieces J, K, L and M are new.

Double-Hole Pin Cube II uses all the above pieces except piece M.
Double-Hole Pin Cube III uses all the above pieces except piece L.

Objective: As with the Double-Hole Pin Cube, the objective for each puzzle is to form a 3x3x3 cube with the 9 pieces. Each puzzle has a single solution. The solutions are considerably different. Fortunately, a little logic can go a long way in solving them.

I really hate to give out the actual solution, as I don't want to rob you of the satisfaction of solving the puzzle yourself. If what you want to do is put the pieces in a nice form for storage, then please consider using a pseudo solution which will fit the pieces in a 4x3x3 box. In this form a single rubber band will hold it together. I don't think this solution will give you any hints about the real solution. However, if you really really must know the real solutions, they can be found here.

Bonus Problems: Pack the 9 pieces of Double-Hole Pin Cube II into each of the two shapes below. There is one solution to each packing. The solution to Bonus 1 is given here and the solution to Bonus 2 is given here. Note that these are the only two ways in which this puzzle can be packed in a 4x3x3 box such that all holes are occupied by a pin. Of course there are 9 empty cube locations. (Solutions that involve simply creating the 3x3x3 cube and dropping it in the box don't count.) The Double-Hole Pin Cube III has no solution to the 4x3x3 problem. Bonus 1 Bonus 2

Soon to come: individual pseudo solutions and solution logic.

I have a few of these puzzles left (made with maple). I prefer to swap for other puzzles of comparable value, but might consider selling. Email puzzles1@mechanicalpuzzles.org.