Quercetti Quercetti is an Italian toy designer that has a variety of different lines. The SkyRail and Marble Run sets are new ways for kids to play with marbles, and the Geosphere set allows for exploration into 3-D building. Marble Run Quercetti Marble Run sets feature plastic easily buildable pieces that allow you to send you marbles and fantastic journeys through spirals and speeding down ramps. SkyRail SkyRail sets are 21st century marble runs that work on thin suspension tracks. Geosphere Geosphere is a plastic 3D building toy that can be assembled in countless different ways.