A freestanding spiral tower marble run wraps a continuous, descending corkscrew track of curved cardboard segments around a central vertical structural pillar, producing a compact 360-degree kinetic sculpture. This design uses a tall cardboard carpet roll, wrapping paper core, or stacked mailing tube as the central support column, anchored into a wide, weighted cardboard base box. Slit and curved paper towel roll segments are fastened around the pillar in a smooth, continuous spiral staircase, allowing the marble to orbit the tower rapidly from summit to base. The standalone format lets multiple children stand around the tower simultaneously, observing centrifugal force and continuous momentum from every angle.
Begin construction by cutting a sturdy twelve-inch square cardboard base plate, gluing an upright, three-foot-tall heavy cardboard mailing tube or wrapping paper core to the center using generous hot glue and reinforcing corner triangular gussets. Prepare twelve paper towel rolls by slitting one side lengthwise and making short, half-inch vertical relief snips along the bottom edges every inch, allowing the cardboard cylinders to curve smoothly without kinking. Starting three inches below the top of the central column, glue the first curved tube segment to the pillar at a steady twenty-degree downward angle. Continue attaching overlapping tube segments in a continuous downward spiral around the circumference of the pillar, ensuring each joint is smooth and free of interior ledges. Add a flared cardboard funnel at the very top of the tower, and glue a circular catch tray around the base plate to contain the finished marble.