Happy 50th anniversary to the mesmerizing, absolutely iconic Gravitram! Completed in 1973, the Gravitram is one of the oldest exhibits at the museum. The 10-foot-high mechanical sculpture took more than 500 hours to build, its balls travelling through intricate gates and switches in an endless labyrinth. How did this mechanical wonder come to be? OMSI Exhibit Designer Shab Levy began tinkering with his friend George Hohnstein on lunch breaks, the design gaining in complexity and popularity until