The holes are placed on different sides and on different levels to create interesting spaces to explore.
They will explore the middle holes.
Even if it means stepping up on the lip of the table from a stool to get the needed leverage to stuff the bedding down the hole. (Is that a dangerous move? The child looks pretty stable, so I did not think I needed to intervene.)
This apparatus is sturdy enough to use outside of the sensory table. I set it up near the block area where I also keep our little cars. Here you can see it became a garage. Cars were obviously driven around the edges, but many ended up in the holes.
And as long as we are talking about exploring holes, there is no better way to explore them than to use your body.
There is one more point to make about holes. Children will find them even if they may not be a part of the apparatus. If you look at the original apparatus, there is a bridge that connects a small table that holds many of the utensils we use in the table. Watch my friend Alex and see what hole he has found.
If you want to know why this redirection works so well, you may want to take a look at my very first blog entry back in July of 2010 here. In the post I talk about the importance of using a pail next to the sensory table. See if you see any "holes" in my logic.