In PLTW, when I was building my cube. I sat and thought about how I was going to build each piece, how each of my five pieces was going to be and how to make it fix into one whole square.  (3 by 3)  First I started with the hardest piece which was the orange piece, and then I moved on to the red. I want to make it even more challenging to I started to think what pieces I could make to be difficult for people to get, and also fix in the square. After all my thinking and building I came up with a hard, challenging, difficult puzzle cube.