docs: public void checkOneObservationPerView() {
  		for (int viewIdx = 0; viewIdx < views.length; viewIdx++) {
  			SceneObservations.View v = views[viewIdx];
  
  			for (int obsIdx = 0; obsIdx < v.size(); obsIdx++) {
  				int a = v.point.get(obsIdx);
  				for (int i = obsIdx+1; i < v.size(); i++) {
  					if( a == v.point.get(i)) {
  						new RuntimeException("Same point is viewed more than once in the same view");
  					}
  				}
  			}
  		}
  	}