Сonditional fusion of two arrays : I have two arrays:

    $array1 = [1, 2, 3];
    $array2 = ['a', 'b', 'c'];

Please tell me how to get to the output I received:

    $array3 = [
        1 => 'a',
        1 => 'b',
        1 => 'c',
        2 => 'a',
        2 => 'b',
        2 => 'c',
        3 => 'a',
        3 => 'b',
        3 => 'c',
    ];

