argh!! no!!! im soo sorry - i cant even read my own diagrams right. ishamael and ladypine both have it right, and I originally did mean to make b = 111, only failed to read my own diagram correctly, so screwed it all up. Im now going back to corrct all my maths mistakes based upon that for the past week or so :(
Lesson learnt? I am a wuckfit at times
