Fluent interfaces

<?php
class Cupboard
{
    protected $_items;

    public function addItem($item)
    {
        $this->_items[] = $item;
        return $this;
    }
    public function removeItem($item)
    {
        $key = array_search($item, $this->_items);
        unset ($this->_items[$key]);
        return $this;
    }
    public function listItems()
    {
        return implode(', ', $this->_items);
    }

}

$cb = new Cupboard();
echo $cb->addItem('plate')
        ->addItem('cup')
        ->addItem('spoon')
        ->addItem('fork')
        ->removeItem('spoon')
        ->listItems() . PHP_EOL;