The Sims 2 log roller as a treadmill, for when you do not want to use a modern looking treadmill.
The stripes on the log move in toward the center of the log while in use. I believe this is because of the way the treadmill belt was designed in order to give the illusion of movement. (It was obviously not designed for a striped log.)
I did make a recolor with no line, but the bark still has the moving toward the center effect:
*note* The Sims do have to walk through the outer logs and on the "water" in order to get onto the log.