title: Simplify (a + b) XOR (c + b)
body: <p>Is it possible to simplify <strong>(a+b)xor(c+b)</strong>? What is the contribution of <strong>b</strong> to the final result?
  Note that I'm mixing boolean algebra with arithmetic, <strong>xor</strong> is a bitwise exclusive or on corresponding bits and <strong>+</strong> is a standard addition on 8 bits, that wraps around when overflown.
  a, b, c are unsigned char;</p>