To be honest, there is no peons at the moment... but maybe one day. My idea was more about how to make the player know a tower is in construction and not broken. I don't have skills/time to draw animation so I simply made the tower appears slowly from the ground until it reaches its size. Who never looked at a construction site and never saw a huge smoke of earth. That's my second idea... to add some smoke during the construction.

Here is the result and I really like it :)