Benjamin

I was doing a jigsaw puzzle with my family and i began wondering if i could make a program that could deduce what the solution to the puzzle was by knowing what the shapes of the pieces are (4 out, 3 out 1 in ... ). This led me to thinking about the possible combinations of a puzzle if that knowledge is unknown. For example, if you had 4 peices and that's all you know, then there are 24 (4!) possible combinations. But with 9 pieces there is 8! * 4 possibilities. I was wondering if there have been any mathmatical proofs that relate to jigsaw puzzles. particularly ones that deal with the number of possible solutions.

i am attempting to make an rc robot and as a result i need a way to get commands over. Does anyone know any premade or easily makeable (I have almost all basic eletrical components in existance) that would let me send a voltage like i had a cable connecting my robot and the controller. I would like for it to be compact and be able to have many lines of transmission if possible.