to run:
py observing1br2and3.txt --grid-size 500 --interval 100
or
python observing1br2and3.txt --grid-size 500 --interval 100
to run:
py observing1br2and3.txt --grid-size 500 --interval 100
or
python observing1br2and3.txt --grid-size 500 --interval 100