I cannot find an app I had an app on my ipad a while ago. I cant remember the name of it, but I can explain it. 

It starts with thousands of moving specs. You can change the amount of dots, the thickness, color etc.. you can also made them move in different ways by the placement of your fingers. 

Does anybody know what I'm talking about and can you help me out?
Go to the App Store app, then Purchased tab and select Not in this iPad.

This is a list of apps that you used on that iPad and is not installed nowadays. That list should list your program.