function check($queens, &$grid)
{
    resetGrid($grid);
    foreach ($queens as $queen) {
        if (!putQueen($grid, $queen)) {
            return false;
        }
    }
    return true;
}
 public function test_lastEmptySquare()
 {
     $grid = makeEmptyGrid();
     putQueen($grid, [0, 0]);
     $this->assertEquals([7, 6], lastEmptySquare($grid));
 }