grasslands.php, strawhouse.php, woodhouse.php, stonehouse.php, and ironhouse.php are faithful translations of Pieter Hintjens' examples of the same names, which he originally published as part of his blog post Using ZeroMQ Security (part 2).  http://hintjens.com/blog:49
The ZMQCert class wraps the CZMQ zcert API. Instances of the ZMQCert class can: * have their public and private text inspected, either as 32-byte binary strings or Z85 armoured strings * be tested for equality * be cloned * store and retrieve metadata * have their public and private test saved to and loaded from disk be applied to a ZMQSocket
* Try and build against the pre-built version of ØMQ, which are stored in a separate support repo * If there isn't a matching pre-build version of ØMQ, then download and build it as before * Fork the run-tests.sh script to travis/script.sh to make it clear that the Travis CI build is distinct  https://github.com/phuedx/php-zmq-travis-support
http://www.php.net/manual/en/class.zmq.php#zmq.constants.mode-dontwait MODE_NOBLOCK is now a deprecated constant.