Also an efficient spring layout with edges that automatically avoid nodes and that are optimized for minimal crossings was implemented by Julien Fierz and part of the code at some point in time.
I did not know this one.
Julien used it in his back-in-time debugger to visualize flow of data in a (potentially large) graph of objects.
Also the original Squeak/Pharo code had anti-aliasing.
Lukas