Hello, It was a fun time in our fairly old, (Built in 1963) but new to us, house. I had just painted the whole house on a Memorial Day weekend and the yard looked empty. So, I built this nice sand box for our son to enjoy the backyard and his toys. He showed signs of allergies. So, after the clear redwood planks were treated with polyurethane, the added sand was purified/sanitized white sand purchased at the local hardware store. It was long before Lowes or Home Depot. It was called “Nail Apron.” We knew of several cats roaming the neighborhood, so I made a clip on cover to keep the wandering cats away from the purified white sand. It took a little extra time, but it was worth it to cover the whole custom sandbox after usage. When it was hot and a weekend holiday or two, my wife used to go outside in the same sandbox, move the toys over to the side and lay down her beach towel for an afternoon nap or two. It was her alternate beach, when we could not go to our favorite beach due to the weekend crowds. If our son also wanted to go outside with “mommy,” we had an umbrella for him. Now, the “green thingy” was his custom pool for those cooling off days. I could move it into the sandbox and he could slide right into the water and then hang around or get out in the clean white sand for his digging activities. Jnaki The yard was finished and our son now had his own section of the yard. I built in a sliding glass door in the wall of the house and if my wife was not outside, she could see him playing in the custom sandbox from anywhere inside. Some days, he would ride his low style “big wheel” around the yard and make a stop at his own private beach and pool… Later on, he would use his custom scooter for the same routes…YRMV