fun returnCallable(a) {
  return x -> x * a
}

let double := returnCallable(2)
let triple := returnCallable(3)

print(double(2)) // 4
print(triple(2)) // 6

print('----------')

fun outer() {
  let x := 'outside'
  fun inner() {
    print(x)
  }

  return inner
}

let closure := outer()
closure()