Activate the cloning from gameobjects, by other gameobject

please help me I have two gameobjects (called "ball" and "generator"). The "generator" is a gameobject empty than has guarded multiples gameobjects called block1,block2,block3,block4. these are clonate whit in a determinated time. The problem is than, if the ball no cross the block these are clonate in the same place what i want is when the "ball" cross whit a block, activated self the next block. The block1,block2,block3,block4 they are a prefab. Some code to fix it, please [1]: /storage/temp/87952-game.png