It's a balancing act and an art project, challenging and fun. Mahogany wood "rocks" can be stacked countless ways to make beautiful, gravity-defying sculptures. Test yourself or compete with a friend to see who can make the tallest tower, or the most amazing, or finish the fastest. Set of 6 includes 2 each small, medium, and large in a burlap drawstring bag. Large is about 3". Handmade in USA.