package main

import "fmt"

type mover interface {
	move()
}

type animal struct {
	name string
}

type bird struct {
	animal
}

func (b bird) move() {
	fmt.Printf("%s flies.\n", b.name)
}

type fish struct {
	animal
}

func (f fish) move() {
	fmt.Printf("%s swims.\n", f.name)
}

func main() {
	creatures := []mover{
		bird{animal: animal{name: "Robin"}},
		fish{animal: animal{name: "Nemo"}},
	}

	for _, c := range creatures {
		c.move()
	}
}