def fib(i: Int, j: Int): Stream[Int] = {
 case 0 | 1 => current
 case _ => Fib( current-1 ) + Fib( current -2 )

}

def fib(i: Int, j: Int): Stream[Int] = i #:: fib(j, i + j)
println(fib(0,1).take(10))

val fibs: Stream[BigInt] = 0 #:: 1 #:: ( fibs zip fibs.tail map ( n => n._1 + n._2 ) )

val fibs: Stream[BigInt] = {
  def loop( h:BigInt, n:BigInt ): Stream[BigInt] = h #:: loop( n, h+n )
  loop(0,1)
}