First, the common base was made, which later on underwent minor adjustments for each character, as I deemed fit, to add variety. From my knowledge of folding a cube, the base was plotted out on graph paper. Then, the character was drawn on top. I started out with the Yogi and then made a rough prototype. At first, the Yogi was the only character, but when I realised that people liked it and responded to it, I thought it might be a good idea to expand it and make a set. Often when working on a project, I tend to get tired of it visually, and it stops losing its character. Most of these times I continue working till I get it right, but then fail to understand why people like what they see :P
Once the Yogi was finalised I took it into Coreldraw and vectored it up. Then with a readymade base, it was easy to continue the series. A Rakshasa ensued, and I managed to altogether avoid picking up a pencil to sketch it. Everything was roughed out and laid out digitally. And so it was with the two other characters. As you will notice, they all fit neatly on to an A4 and are provided with a small set of instructions for ease of use.
The best part? They're free. You can download them here.
Have fun ;)