Using array objects

new.coffee

initBuffer = (len)->
  buffer = new ArrayBuffer(len)
  stack = new Uint8Array(buffer);
  for i in [0..len] by 2
    stack[i] = 0;
    stack[i+1] = 1;
  stack

regress = ()->
  stack = initBuffer(4)
  overwrite = 0
  (result)->
    stack[(overwrite++%4)] = 0
    sum = 0
    for i in stack
      sum += i
    if sum is 2 then Math.RandomInteger(0,1)
    else if sum > 2 then 0 #based on resent history guess differently
    else 1