Rapa Nui people placed red stone 'hats ' or pukao on some of the statues . Oregon University say they may have used ramps to raise the stones . Comment: Some 100 pukao have been found on the remote island in the Pacific Ocean .
Rapa Nui people placed red stone 'hats ' or pukao on some of the statues . Oregon University say they may have used ramps to raise the stones . The team used physics to model possible methods of raising the 'hats ' Some 100 pukao have been found on the remote island in the Pacific Ocean .