What is processing.py
processing.py is a port of processing to python based on jython and hence it can access vanilla processing libraries. The tools folder contains some useful tools for processing.py for using jEdit as an ide. Until processing.py gets its own mode in the regular processing ide, even non linux users will find my jEdit tools be handy. The examples demonstrate the terse syntax of python (cf java and even regular processing in some instances).
pyprocessing is a pure python based implementation of processing, based on the pyglet games engine. I find Eric5 to be an excellent ide for pyprocessing. The advantage of the pure python implementation is access to python libraries such as scipy and numpy. But this is more than outweighted by relatively poor performance, the lack of easy access to processing-2.0 features, and java libraries.