Unlock the entire Houzz
jps play area for your dad
I like the round base for the play area. It is low, which I don't really like. But it is simple and classy.
brick would be really pretty. I love brick and there is so much you can later do with it.
the wall behind the sand box is nice and you can sit on it and watch the kids play which would be a double bonus.
this is nice. you have the slate and a sitting wall. you would have to have an opening if it was this high. but nice to sit on.