Roaring Skyscraper: What level makes it look like a completed building?

At lvl 15 it's fully build. But my opinion would be that you don't have to upgrade it to lvl 15 for the effect...

The effect makes your game almost unplayable and could trigger some epileptic seizure due to the flashing and flickering lights.

I switched it off within the very first minute.

It's good for the population though...