Creating GUI

Whenever I try to make GUI it doesn’t work.
Here is a simple script I wrote:

using UnityEngine;
using System.Collections;

public class GuiTest : MonoBehaviour {

void OnGui()
	GUI.Box(new Rect(0, 0, 50, 50), "Gui Example");


After linking it to a GameObject and clicking the Play button nothing happened…I know the code is correct because it’s a part of the tutorial here: Tutorial

Case matters. ‘OnGui’ is not ‘OnGUI’. Change line 3 to:

void OnGUI()