gistfile1.go

        a := NewAmphibian()
        a.Accelerate(10)
        a.Swim(true)
        a.Accelerate(20)
        fmt.Printf("amphibian speed swimming: %d kph\n", a.Speed())
        a.Swim(false)
        fmt.Printf("amphibian speed on land: %d kph\n", a.Speed())

        var d Drivable
        d = a
        fmt.Printf("amphibian speed on land (as drivable): %d kph\n", d.Speed())
        a.Swim(true)
        fmt.Printf("amphibian speed swimming (as drivable): %d kph\n", d.Speed())