The game ball hats at level 88 now, well to consider the following explanation:
Pull down the existing hat on the top left, and drag it to the left hats is on the right (see the arrows in the figure below).
Then the upside hat on the right, and enter the ball into the hat that had been reversed. After the ball into the hat, the ball will fall into each hat and the door will open floor 88.
Now continue to the 100 floors level 89-90 explanation, or back to the 100 floors level 86-87 explanation