The Helix Tree is a marble run (science toy) designed by Yukari. This project began last year when she finally acquired a 3D printer, which she had long desired. The design resembles a Christmas tree, but as the process of designing and trial-and-error continued, Christmas passed, leading to its name, The Helix Tree.

When you rotate the handle on one of the snowflake-shaped gears clockwise, a spiral running through the center of the tree trunk lifts the balls. This mechanism, widely used in ball-lifting devices, is unique in The Helix Tree as it lifts balls simultaneously at three points. The lifted balls then roll along the green spirals, which represent the tree's leaves, and energetically fall onto the yellow dish, where they spin. Even if the balls temporarily jam on the dish, collisions among them help clear the jam, guiding them back onto the upward spiral. At the top of the tree, there is a decorative small stellated dodecahedron. The direction in which the balls roll down and