This is code for the tutorial at https://hackernoon.com/learn-blockchains-by-building-one-117428612f46 with my revisions.
install python 3 if needed: ``$ brew install python3, test with:
$ python3`
$ virtualenv -p python3 venv
$ source venv/bin/activate
$ pip3 install -r requirements.txt
python3 hash-example.py -x 5 -n 5
this example shows how Proof of Work algorithm works with a simple hashing algorithm. Default x=5 and n=5 if no arguments are provided.