php多态

<?php
abstract class Tiger {
    public abstract function mashu();
}

// 西伯利亚虎？
class XTiger extends tiger{
    public function mashu()
    {
        echo '碎下来了';
    }
}
// 孟加拉虎
class MTiger extends tiger
{
    public function mashu()
    {
        echo '爬到树顶上去了';
    }
} 
class cat
{
    public function mashu()
    {
        echo '哥会飞呢';
    }
}
class client {
    public static function call(Tiger $anmi)
    {
        $anmi->mashu();
    }
}
client::call(new XTiger());
client::call(new MTiger());
client::call(new cat());