Bouncing Ball at constant speed

I need a ball to bounce around inside 4 walls and not lose it’s speed. Pong without paddles if you will.

I’ve searched through the forums a lot, but none of the solutions seem to have addressed this, only 1 axis bouncing is around.

How could I achieve this? Thanks!

I’m doing this right now, yeah it can be improved, but I just wanted it to work for now.

#pragma strict

var speed : float;

function Start () {
	rigidbody.velocity = Vector3 (speed,0,speed);
}

function Update () {
	
}

function OnCollisionEnter(collision : Collision) {
	
	if (collision.transform.name == "topwall") {
		if (rigidbody.velocity.x < 0 )	{
			rigidbody.velocity = Vector3 (-1 * speed,0,-1 * speed);
		} else {
			rigidbody.velocity = Vector3 (speed,0,-1 * speed);
		}
		
	}
	
	if (collision.transform.name == "bottomwall") {
		if (rigidbody.velocity.x < 0 )	{
			rigidbody.velocity = Vector3 (-1 * speed,0,speed);
		} else {
			rigidbody.velocity = Vector3 (speed,0,speed);
		}
		
	}
	
	if (collision.transform.name == "leftpaddle") {
		if (rigidbody.velocity.z < 0 )	{
			rigidbody.velocity = Vector3 (speed,0,-1 * speed);
		} else {
			rigidbody.velocity = Vector3 (speed,0,speed);
		}
		
	}
	
	if (collision.transform.name == "rightpaddle") {
		if (rigidbody.velocity.z < 0 )	{
			rigidbody.velocity = Vector3 (-1 * speed,0,-1 * speed);
		} else {
			rigidbody.velocity = Vector3 (-1 * speed,0,speed);
		}
		
	}
	
	print (rigidbody.velocity);
}

Gonna take a break now. Long Unity learning day.

Thanks man