Nothing like a tissue box

Henry's inch worm move has begun to resemble a crawl. He still belly flops after each forward motion but he's gaining control of the movement day by day.  The best way to get him to practice is to put his favorite toy, a tissue box, out of his reach. Why he has selected the tissue box as his favorite, and kept it as his favorite for many days now is a wonder to me.

He can also sit now:

PS - He's playing with the kleenex box.