How to make a led drop in an array.

Hi guys,

Basically what I want, is when I push the okay button. The corresponding led in the array drops down and stays on true. So when I push the okay button again on the right time, in the same row a led drops down and stacks up. 

The idea was to make a little game, some sort of 4 in a row. With two players and a timer, so you have to stack 4 ASAP to get points. 

Maybe you guys can help me where to find information. Or take a look at my VI i dont think its very difficult. But for me it is lol. 

Thanks a lot guys.