& koch curve

let length = 10
let angle = 0.25

fn koch! {
  (0) -> fd! (length)
  (n) -> {
    koch! (dec (n))
    lt! (angle)
    koch! (dec (n))
    rt! (angle)
    koch! (dec (n))
    rt! (angle)
    koch! (dec (n))
    lt! (angle)
    koch! (dec (n))
  }
}

& koch! (3)