Coop #1 - My first stationary coop was built in 2010 from a former horse shoeing stocks that the horses HATED. There were four 6"x6" posts cemented into the ground in something close to a rectangle and then a fifth 6"x6" post set slightly off-center at the front (can't really see it in the picture below but it is the post farthest to the right).
Horse shoeing stocks (far right side, center)

We added the main floor between the four posts and then added a slightly raised floor from there to the fifth post - there are two nest boxes on the front and two more on the back off of this raised, slightly triangular area. We have since added a completely enclosed (top and sides) run around the front and both sides - the back has two large hinged doors that open up and we let the hens out into a large fenced area (that still has lots of grass) when we are at home each day. The completely enclosed run also has about a foot of wire that comes off the bottom and out into the yard and is covered by a few inches of gravel - so far, we haven't had any predator losses (knock on wood) though we know it is always a possibility. We are planning to extend the roofed area for more shade and rain protection and redoing the interior of the enclosed run with sand.
Coop before adding run (when it still had grass!):

Chicks (light brahamas, speckled sussex, one unknown freebie):

Teenagers (still some grass but it is thinning):

Adults (less grass every day):

Slick the rooster (before the hormones kicked in and he attacked hubby one too many times):

One day I'll get a new picture of the coop with the completely enclosed run and the outer fenced area where the hens spend their afternoons and evenings.

Or maybe not - since we have moved and no longer own this coop.