understanding unity rotatation scripting code example

Example: unity rotate object c#

using UnityEngine;// Transform.Rotate example
//
// This script creates two different cubes: one red which is rotated using Space.Self; one green which is rotated using Space.World.
// Add it onto any GameObject in a scene and hit play to see it run. The rotation is controlled using xAngle, yAngle and zAngle, modifiable on the inspector.public class ExampleScript : MonoBehaviour
{
    public float xAngle, yAngle, zAngle;    private GameObject cube1, cube2;    void Awake()
    {
        cube1 = GameObject.CreatePrimitive(PrimitiveType.Cube);
        cube1.transform.position = new Vector3(0.75f, 0.0f, 0.0f);
        cube1.transform.Rotate(90.0f, 0.0f, 0.0f, Space.Self);
        cube1.GetComponent<Renderer>().material.color = Color.red;
        cube1.name = "Self";        cube2 = GameObject.CreatePrimitive(PrimitiveType.Cube);
        cube2.transform.position = new Vector3(-0.75f, 0.0f, 0.0f);
        cube2.transform.Rotate(90.0f, 0.0f, 0.0f, Space.World);
        cube2.GetComponent<Renderer>().material.color = Color.green;
        cube2.name = "World";
    }    void Update()
    {
        cube1.transform.Rotate(xAngle, yAngle, zAngle, Space.Self);
        cube2.transform.Rotate(xAngle, yAngle, zAngle, Space.World);
    }
}