In this simple example, writer.py periodically publishes data for a Square topic, and reader.py subscribes to the topic and prints all the data samples it receives.

Run the following commands in different shells:

$ python reader.py
$ python writer.py

You can run these commands in any order, and you can run multiple instances of the writer and the reader. You can also run any other DDS application that publishes or subscribes to the Square topic. For example, you can use RTI Shapes Demo.