The greatest mystery of Easter Island’s iconic Moai statues is how they were transported from one end of the island to the other without the use of modern technology. The natives insisted to Dutch explorers that the stone behemoths walked themselves, and while this may sound like silly superstition, some clever physics can show how it was possible.

The McKnelly Megalith, erected on MIT’s front lawn last spring by students of the university’s Megalithic Robotics class, demonstrates how massive objects can be moved using minimum force. The structure was built over the course of a few weeks using fiber-glass enforced concrete and a soft foam core. At 2000 pounds, it’s considerably lighter than the 82-ton Moai of Easter Island, but the fact that it can be adjusted with just the push of a finger is still an extraordinary feat. 

Megaliths like MIT’s structure and the Easter Island statues are specially designed to be rolled or shimmied across long distances using carefully calculated movements. As long as the center of the object’s mass is positioned in just the right place, it should be able to be moved with relative ease regardless of its weight.

The way this method could have been used on Easter Island close to 1000 years ago is detailed on MIT Architecture’s website: "In a similar manner to how one might shimmy a refrigerator into place, the Moai were pulled back and forth by ropes, employing momentum to transport these unwieldy megaliths. This (re)discovery brings new meaning to the folklore that the statues 'walked themselves.'"

MIT’s megalith was erected in a similar fashion. At a rate of about 300 feet per hour, a small team teetered the piece to its final position and then hoisted it upright using a rope.

Constructing a full-sized megalith for the university was never intended to be part of the class curriculum. In the spring semester, teaching assistant Carrie Lee McKnelly lost both her parents to a fire, and the students decided to build the structure in their honor. Megaliths are traditionally made to commemorate deceased ancestors, so the project is both a touching tribute and a clever demonstration of ancient architecture.

[h/t: Fast Co. Design]