3 balls loop using collide block and speed block help

hi i am trying to make that this


in the image the middle ball move to up and down colliding with the balls and create a loop movement between balls but my middle ball move to a diagonal movement. this is my blocks



and my aia
pelotaloop.aia (2.9 KB)

how can make to the ball move in the axis y and not a movement diagonal?

Ball2.PointInDirection must point to the direction of the ball1 if you want ball2 up to ball1 (210,200).

And in Ball2.CollidedWith you need to change the direction based on the ball is colliding with, to change the direction of ball2.