Hi Psygorn,
After much looking, rectangle2 node was located here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=7777.1710

There are 4 "new" nodes in file >>>>>>>>>>>>>>"shapes.zip".<<<<<<<<<<<<<<<
(Wayne's shape nodes???)
Unzip the file, and copy the 4 .js files to your %AppData% folder.
For Windows 10, ...AppData\Roaming\nodeeditor\nodes\extensions.

I am so rusty at nodeeditor, it may be that these 4 nodes are not yet integrated into nodeeditor menus. Not sure.
They are coded to hook themselves into the Curves2 menu...
(Circle2, Star2, Polygon2, and Rectangle2)

- Brian