How do I use the Vector2/Vector3 operator (converting Vector2 to Vector3 and vice versa)

The Unity reference describes the following for converting a Vector2 to Vector3.

*Vector2.operator Vector3

static implicit function Vector3 (v : Vector2) : Vector3
Description
Converts a Vector2 to a Vector3.

Vector2s can be implicitly converted to Vector3 (z is set to zero in the result).*

I've played around with this a bit, but I'm not sure how to get it working - could someone show me an example.

It means you can do stuff like this:

var o1o : Vector3 = Vector2(0,1);   // UnityScript
Vector3 o1o = new Vector2(0,1); // C#

(However, you can also get the same result from using the "xy" Vector3 constructor):

var o1o : Vector3 = Vector3(0,1);   // UnityScript
Vector3 o1o = new Vector3(0,1); // C#

This kind of thing starts to become helpful when you have functions that take a Vector3 as a parameter, but you're only working in 2D. For example, maybe you want to create a UV transformation matrix with Matrix4x4.TRS. In that case, the position variable is only going to be a Vector2, as UV space is two-dimensional. So, despite the fact that the function requires a Vector3, you can send it a Vector2 without any problem.

That means they have overloaded the attribution operator “=”; therefore you can simply attribute a Vector3 to Vector2 and vice-versa.

Vector2 v2 = Vector3.one;
Vector3 v3 = Vector2.one;

You don’t even need to cast.

public Vector2 myVector2D;
public Vector3 myVector3D;

Vector2 myResult2D = myVector2D + (Vector2) myVector3D; 
Vector3 myResult3D = (Vector3) myVector2D +  myVector3D;