My latest design is based on the fact that there are different possibilities to cut a unit cube into two half cubes with a single straight cut. The most interesting one is a cut that produces a regular hexagon in the cutting plane with the cube. Using nine pieces each having a volume of 3 units (2 unit cubes and two half cubes as described) you can assemble them to get a cube of the size 3x3x3. And here is the puzzle:

Lifting the box shows the assenbled cube:

It is interesting to know that all nine pieces are different. And for sure there is only one solution to this puzzle :-)
For the pieces three different types of wood are used. Here a picture that shows the puzzle partly disassembled. There you can see the beautifully made diagonal cuts.

Want to see the cut in more detail? Here it is: