function blockValues($board, $coord)
{
    $result = [];
    $coord_pairs = coordPairs(blockHelper($coord));
    foreach ($coord_pairs as $coord) {
        $result[] = $board[$coord[0]][$coord[1]];
    }
    $values = array_values(array_unique($result));
    sort($values);
    return $values;
}
 public function test_coordPairs()
 {
     $this->assertEquals([[6, 6], [6, 7], [6, 8], [7, 6], [7, 7], [7, 8], [8, 6], [8, 7], [8, 8]], coordPairs([6, 6]));
     $this->assertEquals([[0, 3], [0, 4], [0, 5], [1, 3], [1, 4], [1, 5], [2, 3], [2, 4], [2, 5]], coordPairs([0, 3]));
 }