Traffic lights example with golang

package main

import (
	"fmt"
	"time"
)

func main() {
	closeChan := make(chan struct{})
	go func() {
		time.Sleep(time.Second * 10)
		closeChan <- struct{}{}
	}()

	trafficLight := TrafficLight{
		Colours: []string{"red", "red amber", "green", "amber"},
		Delay:   time.Second * 2,
		Close:   closeChan,
	}

	trafficLight.On()
}

// 1. Red:       Stop
// 2. Red/Amber: Get ready
// 3. Green:     Go
// 4. Amber:     Stop if safe
type TrafficLight struct {
	Colours []string
	Delay   time.Duration
	Close   chan struct{}
}

func (t TrafficLight) On() {
	go func() {
		tick := time.NewTicker(t.Delay)
		defer tick.Stop()

		len := len(t.Colours)

		for i := 0; i < len; i++ {
			fmt.Println(t.Colours[i])

			if i == len-1 {
				i = -1
			}

			<-tick.C
		}
	}()

	<-t.Close
}