Rolling Ball Sculpture #282 ~ Gravity powered tabletop 2 Gravity Tabletop #273 3 Available – Rolling Ball Sculpture #271 ~ Semi-Automatic Gravity powered tabletop 3 Rolling Ball Sculpture #264 – Semi Automatic Gravity Desktop. 0 “The Hourglass” – semi automatic RBS #263 3 Desktop #245 2 Xylophone Tabletop #214 1 Gravity Tabletop #253 2 Gravity Tabletop #240 1 Gravity Tabletop #159 1