Just a fun way to spend a little time. Test your memory, keep your mind sharp!
I coded this in R2014b. Nonetheless, while I haven't tested it in R13a, I am surprised to hear that it won't open in that version. I don't see anything in the code that requires a more recent version of MATLAB. Can you tell me what message you get when you try to open it?
Does not open in 2013a