Interface Example for bounce

Ball

public class Ball : MonoBehaviour
{
	private IBounce bounce;

	public void Initialize(IBounce bounce)
	{
		this.bounce = bounce;
	}

	void Update () 
	{
		bounce.BounceOnWall(rigidbody2D);
	}
}

BounceLogic

public class BounceLogic : IBounce
{
	private IBounds bounds;
	private IBall ball;
	public BounceLogic(IBall ball)
	{
		this.ball = ball;
		bounds = new BoundsLogic();
	}

	public void BounceOnWall(Rigidbody2D rigidbody2D)
	{
		if ((rigidbody2D.transform.position.x <= bounds.LeftBounds &&
			rigidbody2D.velocity.x < 0) || (rigidbody2D.transform.position.x >= bounds.RightBounds && 
			rigidbody2D.velocity.x > 0))
		{
			rigidbody2D.velocity = new Vector2(ball.Bounce(rigidbody2D.velocity.x),
				rigidbody2D.velocity.y);
		}
		else if ((rigidbody2D.transform.position.y <= bounds.DownBounds &&
			rigidbody2D.velocity.y < 0) || (rigidbody2D.transform.position.y >= bounds.UpBounds &&
			rigidbody2D.velocity.y > 0))
		{
			rigidbody2D.velocity = new Vector2(rigidbody2D.velocity.x,
				ball.Bounce(rigidbody2D.velocity.y));
		}
	}
}

IBounce

public interface IBounce
{
	void BounceOnWall(Rigidbody2D rigidbody2D);
}