fibonacci.php

<?php

function fibonacci($limit){
    $first  = 0;
    $second = 1;
    
    for($i = 0; $i < $limit; $i++){
        yield $first;

        list($first, $second) = [$second, $first + $second];
    }
}

// var_dump(iterator_to_array(fibonacci(10)));

foreach (fibonacci(10) as $key => $result){
    echo sprintf('%s. number: %s%s', ++$key, $result, PHP_EOL);
}