While Loop -I don't understand.

<?php
$headcount=0;
$filpcount=0;

while ($headcount<3) {
    $filp=rand(0,1);
    $filpcount++;

    if($filp)
    {
        $headcount++;
        echo "<div class=\"coin\">H</div>";
    }
    else
    {
        $headcount=0;
        echo "<div class=\"coin_two\">T</div>";
    }
}
echo "<p class=\"tech\">Itz took {$filpcount} flips</p>";



?>