This very tall Rolling Ball Sculpture has just about everything I could pack into it. It has two chain lifts, each with its own speed control, so you can change the pace of different parts of the sculpture independently. With six different tracks, there can be a lot going on at once.

Two tall coils are fed together by a tipping arm that collects two balls and releases them side by side. There are also two flat plates where the marbles are free to roll around before finding their way out. One of the plates is curved, so the ball rolls back and forth before finally escaping. From there the balls turn a spinning wheel, which also lifts a ball onto its own little enclosed track.

The most complicated part is a series of four connected tipping arms. A ball entering the mechanism moves from one arm to the next. As each arm tips, it pushes another waiting ball up and out onto a track. The first ball goes to the second arm, the second to the third, the third to the fourth, and the fourth finally sends its ball back toward the lift. Between the arms are horizontal zig-zags that slow the balls down just enough to give each arm time to reset.

Getting this mechanism to work requires the balls to arrive in the right order. Two loop d’ loop tracks feed the two sides of the mechanism—one supplies the balls waiting to be pushed into play, while the other supplies the balls that activate the tipping arms. I only used this mechanism on this one RBS. It was complicated to build and set up, but it’s a really fun thing to watch when everything starts moving.

Four of the six tracks eventually reach the large wooden gravity well at the bottom, where the balls circle around, drop through the center and head back to the lifts for another trip.

100% stainless steel, TIG welded.