I've actually done something similar. My pdoc sometimes would send me to his office ahead of him or leave for a little bit. So I would move his chair to see if he would notice when he came back in (it was on wheels, a desk chair.) But he never did. He just sat in it and wheeled it where ever he wanted to be. Unless he chose another chair insttead. Oh, well. I even turned some pictures that hadn't been hung yet upside down once. It wasn't really his office so that may be why he didn't notice that. I wonder though if he did look at the mixed up waterfall sometime later and wonder. giggle