I decided to change the name of my symbol node to "shapes". This is more fitting, since some of the options are not really symbols. I changed the description to "A collection of useful shapes".
I also redid the demo to make it easier to maintain (in case I add more shapes). The demo now simply uses my arrange node to arrange the shapes into three rows.
Just for fun, I made a subnetwork, color_pairs, to produce pairs of fill and stroke colors for each shape using my new multi-list data structure. Look inside to see how I did it and increment the offset parameter to see different color combinations. This is a handy technique you could use in a variety of situations.
Version 3.7 of the Cartan Node Library will include shapes in place of symbol with the two new additions described here:
https://forum.nodebox.net/t/8478420652/squircle
https://forum.nodebox.net/t/9144041872/new-symbol-infinity-loop
