Challenges

Software

Debugging
We had many bugs during the process of creating the working code for the prototype, however, everything got figured out by the end of the day. Careful checking is always the best technique for dealing with bugs. 

Hardware

Integration of physical prototype
Fitting the circuit prototype into the physical cubes is not an easy job. We faced many problems such as cannot fit the USB end in the box, instability of the LED matrix, and the stability of the lid. We later re-organize the layout in the box and stabilized some parts firmly to fit everything in our box models. 

Short cut
While we were trying to find out a way to stabilize our circuit at the bottom, we taped the wires up. But it was not a good idea because we got a short circuit from it. One lesson learned from this experience is never to tape circuit up and it could be dangerous.