Corrections and a Jupyter notebook

[Talinf]

Hi,
thanks for your programs. They are fun and interesting.

I noted some small problems:

a_bit_mondrian.py
Running it in python 3 gives an error in the random.choice function because colors is an iterable and not a list.
By changing line 14 to:
colors = list(color_nums.keys())
the problem is resolved.

double_pendulum.py
1- the PATH directive is not terminated properly which gives an XML error.
to correct simply change line 116 from:
path+= '" style="fill-opacity: 0; stroke-width: 2; stroke: green; filter: url(#glow);"'
to
path+= '" style="fill-opacity: 0; stroke-width: 2; stroke: green; filter: url(#glow);" />'

2- the filter is not applied because the tags in the filter definition are in lowercase instead of camelcase:
fegaussianblur must be change to feGaussianBlur
stddeviation to stdDeviation
femerge to feMerge
femergenode to feMergeNode

Funny thing, the lowercase tags works in a Jupyter notebook.

Speaking of Jupyter notebook, I put all your programs in a single Jupyter notebook to facilitate experimentation.
I included the notebook and a sample pdf file in the attached files.

sample.pdf
svg_play_notebook.zip