<?php $tag_list = $tag_chain . $tag_chain;
$all_before_parts = explode($tag_list, $matches['x'][0]);
$tag_last = end($all_before_parts) === '' ? '' : $tag_chain;
$tag_first = reset($all_before_parts) === '' ? '' : $tag_chain;
$core_parts = explode($tag_chain, $all_before_parts[0]);
$elements = '';
$list = self::getList($core->getPlates(), $core_parts);