$re = '/^\[(\[-?\d+(?:\.\d+)?,-?\d+(?:\.\d+)?\])(?:,\[-?\d+(?:\.\d+)?,-?\d+(?:\.\d+)?\])+,\1\]/m';
$str = '[[106.00,-50.00],[109.00,-34.00],[101.00,-29.00],[105.00,-26.00],[116.00,-30.00],[114.00,-50.00]]
[[106.00,-50.00],[109.00,-34.00],[101.00,-29.00],[105.00,-26.00],[116.00,-30.00],[106.00,-50.00]]';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php