We have 3 dogs and our yard isn't fenced in so the wife asked for a pen to be erected. Pretty simple to make as long as you stay consistent with the measurement. Decided not to cement in the corner posts so that we could eventually move it so the task of getting things to remain level was a task all in itself.
Excellent work! This looks like a good compromise to fencing the entire yard, and that was good thinking about keeping it moveable. That will be quiet a convenience if you ever have to transport it somewhere because you won't have to break apart the cement. Great work!