FactHandle[][] handles = new FactHandle[size][];
for ( int row = 0; row < size; row++ ) {
cells[row] = new Cell[size];
handles[row] = new FactHandle[size];
for ( int col = 0; col < size; col++ ) {
cells[row][col] = new Cell( Cell.DEAD, row, col );
handles[row][col] = session.insert( cells[row][col] );
if ( row >= 1 && col >= 1 ) {
// northwest
session.insert( new Neighbor( cells[row - 1][col - 1],
cells[row][col] ) );