Make cart arc

[djps]

This should fix #288

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.53%. Comparing base (0ce15a4) to head (7c33f43).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #343      +/-   ##
==========================================
+ Coverage   67.42%   67.53%   +0.11%     
==========================================
  Files          48       48              
  Lines        7024     7024              
  Branches     1596     1596              
==========================================
+ Hits         4736     4744       +8     
+ Misses       1701     1696       -5     
+ Partials      587      584       -3     

Flag	Coverage Δ
3.10	67.69% <100.00%> (+0.11%)	⬆️
3.11	67.69% <100.00%> (+0.11%)	⬆️
3.12	67.69% <100.00%> (+0.11%)	⬆️
3.9	67.51% <100.00%> (+0.11%)	⬆️
ubuntu-latest	67.48% <100.00%> (+0.11%)	⬆️
windows-latest	67.48% <100.00%> (+0.11%)	⬆️

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[waltsims]

Thanks for taking this on David. The example still didn't run due to a type issue on diameter, which I have addressed. I also updated some of the plotting. By default, it seems matplotlib interpolates the plots, which I turned off to replicate MATLAB behavior.