I also needed this and finally found a solution, here is my code.
Use var size = c.options. Size; I = (((i - 1) % size) + size) % size; instead of --i;. This code fixes the modulus of negative values.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.