Where's Nathan?

Nathan has begun a new trick... At about 8 o'clock this morning I was sitting at the desk in our office working on some homework. I looked outside and noticed that Nathan was outside. Hmmm, the back door is locked... how did he do that? Then I realized - he went through the doggy door in the playroom. Now, I have blocked this doggy door by a table so that it wouldnt be noticeable - or better yet - a temptation. It's okay to be outside - I just want to know about it, so I'm not frantically searching through the house for a missing child. Worse yet, where he likes to sit is up against the house where I can not see him from any window. He likes to sit there and move the rocks around with his hands and feet and then he throws them-on the concrete. This creates the not-so-welcomed task of cleaning them up.
This would'nt be so bad if the rocks were'nt red rocks that dye hands and feet - and displayed in the above picture: faces. Oh well, boys will be boys!
Now it is later in the day and he has done it again. I guess I am going to have to either get use to this, or find a better way to block the door. At least I know where he is!