code: boolean computeCalibrationPoints(SquareGrid grid) {
  		calibrationPoints.reset();
  
  		for (int row = 0; row < grid.rows-1; row++) {
  			int offset = row%2;
  			for (int col = offset; col < grid.columns; col += 2) {
  				SquareNode a = grid.get(row,col);
  
  				if( col > 0 ) {
  					SquareNode b = grid.get(row+1,col-1);
  					if( !setIntersection(a,b,calibrationPoints.grow()))
  						return false;
  				}
  
  				if( col < grid.columns-1) {
  					SquareNode b = grid.get(row+1,col+1);
  					if( !setIntersection(a,b,calibrationPoints.grow()))
  						return false;
  				}
  			}
  		}
  
  		return true;
  	}
docs: Find inner corner points across the grid.  Start from the "top" row and work its way down.  Corners
  are found by finding the average point between two adjacent corners on adjacent squares.