//BALL COLLISION CODE
                    for (int i = 0; i < balls.Count; i++)
                    {
                        for (int j = i + 1; j < balls.Count; j++)
                        {
                            // TODO: Put your collision handling with another ball code here
                            if (balls[i].BoundingSphere.Intersects(balls[j].BoundingSphere))
                            {
                                //moving objects only if both velocity.length > 0
                                if (balls[i].Velocity.Length() > 0 && balls[j].Velocity.Length() > 0)
                                {
                                    Vector3 collisionVector = balls[i].Position - balls[j].Position;
                                    Vector3 collisionVectorj = balls[j].Position - balls[i].Position;

                                    Vector3 velocityOutputI = balls[i].Velocity - ((Vector3.Dot((balls[i].Velocity - balls[j].Velocity), collisionVector)
                                        / collisionVector.LengthSquared()) * collisionVector);

                                    Vector3 velocityOutputJ = balls[j].Velocity - ((Vector3.Dot((balls[j].Velocity - balls[i].Velocity), collisionVectorj)
                                        / collisionVectorj.LengthSquared()) * collisionVectorj);

                                    balls[i].Velocity = velocityOutputI;
                                    balls[j].Velocity = velocityOutputJ;

                                    //MOVE OUT OF WAY CODE
                                    balls[i].Position -= ((balls[j].Position - balls[i].Position).Length() - (balls[i].BoundingSphere.Radius) * 2) * Vector3.Normalize(collisionVector);
                                    balls[j].Position += ((balls[j].Position - balls[i].Position).Length() - (balls[i].BoundingSphere.Radius) * 2) * Vector3.Normalize(collisionVector);
                                }

                                //if one ball is 0
                                else
                                {

                                    //if ball j is moving
                                    float jSpeed = balls[j].Velocity.Length();
                                    float iSpeed = balls[i].Velocity.Length();

                                    if (jSpeed > 0)
                                    {
                                        //create normal to collision vector
                                        Vector3 collisionVector = balls[i].Position - balls[j].Position;
                                        float collLength = collisionVector.Length();

                                        //create normal to the collision vector
                                        Vector3 collisionNormal = new Vector3(-collisionVector.Z, collisionVector.Y, collisionVector.X);

                                        //theta calculation
                                        float dot = Vector3.Dot(-balls[j].Velocity, collisionVector);
                                        float denom = jSpeed * collLength;
                                        float theta = (float)Math.Acos(dot /
                                            denom);

                                        //vector normalization
                                        collisionVector = Vector3.Normalize(collisionVector);
                                        collisionNormal = Vector3.Normalize(collisionNormal);

                                        //MAKE SPECIAL CASE FOR THETA = 0;
                                        if (theta == 0)
                                        {
                                            Vector3 tempVelocity = balls[i].Velocity;
                                            balls[i].Velocity = balls[j].Velocity;
                                            balls[j].Velocity = tempVelocity;
                                        }
                                        else
                                        {
                                            float velocityLengthJ = balls[j].Velocity.Length() * ((float)Math.Sqrt(2 + (2 * (float)Math.Cos(theta))) / 2);
                                            float velocityLengthI = balls[j].Velocity.Length() * (float)(Math.Sin(theta / 2));

                                            //create the new ball velocities
                                            balls[j].Velocity = velocityLengthJ * Vector3.Normalize(collisionNormal);
                                            balls[i].Velocity = velocityLengthI * Vector3.Normalize(collisionVector);
                                        }
                                    }

                                    if (iSpeed > 0)
                                    {
                                        //create normal to collision vector
                                        Vector3 collisionVector = balls[j].Position - balls[i].Position;
                                        float collLength = collisionVector.Length();

                                        //create normal to the collision vector
                                        Vector3 collisionNormal = new Vector3(-collisionVector.Z, collisionVector.Y, collisionVector.X);

                                        //theta calculation
                                        float dot = Vector3.Dot(-balls[i].Velocity, collisionVector);
                                        float denom = iSpeed * collLength;
                                        float theta = (float)Math.Acos(dot /
                                            denom);

                                        //MAKE SPECIAL CASE FOR THETA = 0;
                                        if (theta == 0)
                                        {
                                            Vector3 tempVelocity = balls[i].Velocity;
                                            balls[i].Velocity = balls[j].Velocity;
                                            balls[j].Velocity = tempVelocity;
                                        }
                                        else
                                        {
                                            //vector normalization
                                            collisionVector = Vector3.Normalize(collisionVector);
                                            collisionNormal = Vector3.Normalize(collisionNormal);

                                            float velocityLengthI = balls[i].Velocity.Length() * (float)(Math.Sqrt(2 + (2 * (float)Math.Cos(theta))) / 2);
                                            float velocityLengthJ = balls[i].Velocity.Length() * (float)(Math.Sin(theta / 2));

                                            Vector3 normalizedCollisionN = Vector3.Normalize(collisionNormal);
                                            Vector3 normalizedCollision = Vector3.Normalize(collisionVector);

                                            //create the new ball velocities
                                            balls[i].Velocity = velocityLengthI * normalizedCollisionN;
                                            balls[j].Velocity = velocityLengthJ * normalizedCollision;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }