We have mostly carpet throughout our house, so it is possible that he could have been doing this a lot sooner. Today I had Billy sitting on the bathroom floor while I fixed my hair and make-up and he flopped onto his tummy and started backwards sliding around the floor (it needed a good sweeping anyway). The fun part was when he made it to the pile of empty 2 liter bottles (long story cut short–it is that time of year to refresh the water in our storage anyway). Billy reached up and grabbed one from the middle of the pyramid. They all came cascading down around him and he just sat there looking confused and then he did a little giggle as if to say, “Hey, that was kind of fun.” If he wasn’t so content to just lay there, I would think he was getting ready to chase after Ricky, but for the most part Billy is happy to stay where I put him.