<?
$shop = array(
array("1", "red", "black", "blue and green"),
array("2", "orange"),
array("2", "pink", "yellow")
);

for ($row = 0; $row < 3; $row++)
{
    echo "<li><b>The row number $row</b>";
        echo "<ul>";
                for ($col = 0; $col < 3; $col++)
                {
                    if (in_array($col, explode(' and ', $_GET['filter']))){
                        echo "<li>".$shop[$row][$col]."</li>";
                    }
                }
        echo "</ul>";
    echo "</li>";
}

?>