http://imgur.com/a/lP97R
I'm finally done with my skulls, it took me about a month. :)
Now I'll upgrade the inner circle walls to level 9 and then I'll start upgrading my defense. :)
I started upgrading my walls, because I had no more fun upgrading defensive buildings, so I had 4 free builders for a month (sometimes I upgraded things like mines, pumps and storages), but soon they'll be all working.

