private boolean isPlaceable(final int col, final int row) {
		Boolean placeable;
		if (row < 0 || row >= size) {
			throw new IllegalArgumentException(
					"isPlaceable : row " 
					+ row + "parameter out of bounds, must be between 0  and " 
					+ size);
		}
		if (col < 0 || col >= size) { 
			throw new IllegalArgumentException(
					"isPlaceable : col " 
					+ col + "parameter out of bounds, must be between 0  and " 
					+ size);
		}
		if (board[col][row] == PositionStatus.UNSAFE  
				|| board[col][row] == PositionStatus.OCCUPIED) {  
			placeable = false;
		} else { 
			placeable = true;
		}
		return placeable;
	}