TeXmacs looks sort of interesting.
Should write something that's like
a cross between xpenguins and civilization;
An empire-building game that fits on the bottom
of the root window, or something.
Trying to understand in general what kind of diagrammatic interactions between degree-three nodes actually read sensibly in the lambda calculus:
Not sure this is the simplest possible inverse (or even that it is correct) but it makes for a fun diagram: