linear congruential generators

<?php
// rand initial number(seed)
    $lc_seed = 1;
// random function
    fuction lc_rand() {
        global $lc_seed;
        $MASK = 0xffffffff;
        $lc_seed = (1103515245 * $lc_seed + 12345) & $MASK;
        return ($lc_seed / 65536) % 32768;
    }
// initialize random function
    function lc_srand($seed) {
        global $lc_seed;
        $lc_seed = $seed;
    }
// example
    lc_srand(time());
    $list = array('●','▲','■','◯','△','□');
    for ($i = 0; $i < 256; $i++){
        $c = $list&#91;lc_rand() % 6&#93;;
        echo $c;
        if ($i % 16 == 15) echo "<br>";
    }